/* 页间 Folio 官网 —— 纯静态，无构建步骤 */

:root {
  --paper: #f6f3ec;
  --paper-2: #efeadf;
  --card: #fffdf8;
  --ink: #1b211e;
  --ink-2: #464e49;
  --ink-3: #7a817c;
  --line: #e2dccf;
  --line-2: #d6cfbf;

  --green-950: #0c2621;
  --green-900: #153b33;
  --green-800: #1b4a40;
  --green-700: #22594d;
  --green-600: #2a6a5c;
  --green-500: #3d8574;
  --green-100: #e2ede7;

  --gold: #e2bb63;
  --gold-soft: rgba(226, 187, 99, 0.45);
  --coral: #c1462f;
  --pen: #d6453a;
  --violet: #6a5ae0;
  --violet-soft: #b9adff;

  /* 深色区块 */
  --night: #0b1411;
  --night-2: #101c18;
  --night-ink: #f3efe4;
  --night-ink-2: rgba(238, 233, 220, 0.7);
  --night-ink-3: rgba(238, 233, 220, 0.48);
  --night-line: rgba(255, 255, 255, 0.09);

  --serif:
    'Songti SC', 'Noto Serif SC', 'Source Han Serif SC', 'Source Han Serif CN', 'STSong', 'SimSun',
    serif;
  --sans:
    -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei',
    'Noto Sans SC', 'Helvetica Neue', Arial, sans-serif;
  --hand: 'Kaiti SC', 'STKaiti', 'KaiTi', 'BiauKai', 'Kaiti TC', serif;
  --latin: 'Iowan Old Style', 'Palatino Linotype', Palatino, Georgia, serif;
  --mono: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;

  --radius: 18px;
  --shadow-sm: 0 1px 2px rgba(22, 44, 38, 0.06), 0 2px 8px rgba(22, 44, 38, 0.05);
  --shadow-lg:
    0 0 0 1px rgba(22, 44, 38, 0.07), 0 2px 4px rgba(22, 44, 38, 0.04),
    0 24px 48px -12px rgba(22, 52, 44, 0.22), 0 60px 120px -40px rgba(22, 52, 44, 0.35);
  --ease: cubic-bezier(0.22, 0.8, 0.24, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
  -webkit-text-size-adjust: 100%;
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.75 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: clip;
}
img {
  max-width: 100%;
  height: auto;
}
a {
  color: var(--green-600);
  text-decoration: none;
}
a:hover {
  color: var(--green-800);
}
h1,
h2,
h3 {
  margin: 0;
  font-weight: 700;
  color: var(--ink);
}
p {
  margin: 0;
}
figure {
  margin: 0;
}
code {
  font: 0.88em/1 var(--mono);
  background: rgba(34, 89, 77, 0.08);
  color: var(--green-800);
  padding: 0.18em 0.42em;
  border-radius: 6px;
}
kbd {
  display: inline-block;
  min-width: 1.7em;
  padding: 0.1em 0.42em;
  margin: 0 0.08em;
  font: 600 0.82em/1.5 var(--sans);
  text-align: center;
  color: var(--ink-2);
  background: var(--card);
  border: 1px solid var(--line-2);
  border-bottom-width: 2px;
  border-radius: 6px;
  vertical-align: 0.08em;
}
:focus-visible {
  outline: 2px solid var(--green-500);
  outline-offset: 3px;
  border-radius: 6px;
}
.icon {
  width: 1em;
  height: 1em;
  flex: none;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.skip {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 100;
  padding: 8px 14px;
  background: var(--ink);
  color: #fff;
  border-radius: 8px;
}
.skip:focus {
  top: 12px;
  color: #fff;
}

.container {
  width: min(1120px, 100% - 48px);
  margin-inline: auto;
}
.container-wide {
  width: min(1240px, 100% - 48px);
  margin-inline: auto;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55em;
  font: 600 15px/1 var(--sans);
  border-radius: 12px;
  padding: 12px 18px;
  border: 1px solid transparent;
  cursor: pointer;
  white-space: nowrap;
  transition:
    transform 0.2s var(--ease),
    box-shadow 0.2s var(--ease),
    background-color 0.2s,
    color 0.2s,
    border-color 0.2s;
}
.btn .icon {
  font-size: 1.15em;
  stroke-width: 2;
}
.icon-fill {
  fill: currentColor;
}
.btn-sub {
  font-weight: 500;
  color: var(--ink-3);
  font-variant-numeric: tabular-nums;
}
.btn-sm {
  font-size: 14px;
  padding: 9px 14px;
  border-radius: 10px;
}
.btn-lg {
  font-size: 17px;
  padding: 17px 28px;
  border-radius: 14px;
}
.btn-primary {
  background: linear-gradient(180deg, var(--green-600), var(--green-800));
  color: #fdfbf5;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.16),
    0 1px 2px rgba(15, 46, 40, 0.3),
    0 8px 20px -6px rgba(21, 59, 51, 0.5);
}
.btn-primary:hover {
  color: #fff;
  transform: translateY(-1px);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.18),
    0 2px 4px rgba(15, 46, 40, 0.3),
    0 14px 28px -8px rgba(21, 59, 51, 0.55);
}
.btn-ghost {
  background: rgba(255, 253, 248, 0.6);
  color: var(--ink);
  border-color: var(--line-2);
}
.btn-ghost:hover {
  color: var(--ink);
  background: var(--card);
  border-color: var(--ink-3);
}
.btn-light {
  background: #fdfbf5;
  color: var(--green-900);
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
}
.btn-light:hover {
  color: var(--green-950);
  transform: translateY(-1px);
  background: #fff;
}
.btn-dim {
  background: rgba(255, 255, 255, 0.08);
  color: #fbf7ec;
  border-color: rgba(235, 229, 215, 0.22);
}
.btn-dim:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.14);
  border-color: rgba(235, 229, 215, 0.4);
}
.btn.is-disabled {
  pointer-events: none;
  filter: grayscale(0.7);
  opacity: 0.55;
  box-shadow: none;
}

/* ---------- Nav ---------- */
.nav {
  position: fixed;
  inset: 0 0 auto;
  z-index: 50;
  transition:
    background-color 0.3s,
    box-shadow 0.3s,
    backdrop-filter 0.3s;
}
.nav.is-scrolled {
  background: rgba(246, 243, 236, 0.78);
  -webkit-backdrop-filter: saturate(1.4) blur(16px);
  backdrop-filter: saturate(1.4) blur(16px);
  box-shadow: 0 1px 0 rgba(22, 44, 38, 0.08);
}
.nav-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 68px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
}
.brand:hover {
  color: var(--ink);
}
.brand img {
  width: 30px;
  height: 30px;
}
.brand-cn {
  font: 700 20px/1 var(--serif);
  letter-spacing: 0.06em;
}
.brand-en {
  font: 500 19px/1 var(--latin);
  color: var(--ink-2);
  margin-left: -2px;
}
.nav-links {
  display: flex;
  gap: 4px;
  margin-left: auto;
}
.nav-links a {
  padding: 8px 12px;
  font-size: 14.5px;
  color: var(--ink-2);
  border-radius: 8px;
  transition:
    color 0.2s,
    background-color 0.2s;
}
.nav-links a:hover {
  color: var(--ink);
  background: rgba(34, 89, 77, 0.07);
}

/* 返回向小园个人主页（helloxxy.com）的面包屑 */
.xy-crumb {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}
.xy-home {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0;
  color: inherit;
  opacity: 0.55;
  white-space: nowrap;
  text-decoration: none;
  transition: opacity 0.2s;
}
.xy-home:hover {
  opacity: 1;
  text-decoration: none;
}
.xy-sep {
  font-size: 14px;
  opacity: 0.25;
  user-select: none;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 150px 0 0;
  isolation: isolate;
  overflow-x: clip;
}
.hero::before {
  /* 横线笔记纸 */
  content: '';
  position: absolute;
  inset: 0 0 40%;
  z-index: -1;
  background-image: repeating-linear-gradient(
    to bottom,
    transparent 0 39px,
    rgba(34, 89, 77, 0.075) 39px 40px
  );
  -webkit-mask-image: radial-gradient(ellipse 60% 70% at 50% 30%, #000 20%, transparent 72%);
  mask-image: radial-gradient(ellipse 60% 70% at 50% 30%, #000 20%, transparent 72%);
}
.hero-glow {
  position: absolute;
  left: 50%;
  top: 40%;
  z-index: -1;
  width: min(1500px, 140vw);
  aspect-ratio: 1.9;
  transform: translateX(-50%);
  background:
    radial-gradient(closest-side, rgba(61, 133, 116, 0.24), transparent) 12% 40% / 56% 76% no-repeat,
    radial-gradient(closest-side, rgba(106, 90, 224, 0.14), transparent) 88% 30% / 50% 70% no-repeat,
    radial-gradient(closest-side, rgba(226, 187, 99, 0.28), transparent) 66% 64% / 52% 70% no-repeat;
  filter: blur(24px);
}
.hero-copy {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.hero-title {
  position: relative;
  font: 700 clamp(50px, 8vw, 112px) / 1.12 var(--serif);
  letter-spacing: 0.03em;
  color: var(--ink);
}
.hero-title .line {
  display: block;
}
.mark {
  position: relative;
  white-space: nowrap;
  background: linear-gradient(
      transparent 58%,
      var(--gold-soft) 58%,
      var(--gold-soft) 90%,
      transparent 90%
    )
    no-repeat 0 0 / 100% 100%;
  padding: 0 0.04em;
  margin: 0 -0.04em;
}
.js .mark {
  background-size: 0% 100%;
  animation: sweep 0.9s 0.55s var(--ease) forwards;
}
@keyframes sweep {
  to {
    background-size: 100% 100%;
  }
}
.hand-note {
  position: absolute;
  left: calc(100% + 4px);
  bottom: 0.5em;
  width: max-content;
  font: 400 26px/1.45 var(--hand);
  color: var(--coral);
  letter-spacing: 0.04em;
  text-align: left;
  transform: rotate(-6deg);
  transform-origin: 0 100%;
}
.hand-note::before {
  /* 指向“读得懂”的小箭头 */
  content: '';
  position: absolute;
  left: -46px;
  top: 58%;
  width: 40px;
  height: 22px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 40 22'%3E%3Cg fill='none' stroke='%23c1462f' stroke-width='1.8' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M38 5C27 3 14 7 4 17'/%3E%3Cpath d='M4 9v8.5h8.5'/%3E%3C/g%3E%3C/svg%3E")
    no-repeat center / contain;
}
.hand-note svg {
  display: block;
  width: 100%;
  height: 12px;
  margin-top: 2px;
}
.hand-note path {
  fill: none;
  stroke: var(--coral);
  stroke-width: 2.4;
  stroke-linecap: round;
}
.js .hand-note {
  opacity: 0;
  animation: note-in 0.8s 1.2s var(--ease) forwards;
}
.js .hand-note path {
  stroke-dasharray: 280;
  stroke-dashoffset: 280;
  animation: draw 0.9s 1.6s var(--ease) forwards;
}
@keyframes note-in {
  from {
    opacity: 0;
    transform: rotate(-6deg) translateY(8px);
  }
  to {
    opacity: 1;
    transform: rotate(-6deg);
  }
}
@keyframes draw {
  to {
    stroke-dashoffset: 0;
  }
}
.hero-lead {
  max-width: 660px;
  margin-top: 28px;
  font-size: clamp(17px, 1.6vw, 19.5px);
  line-height: 1.9;
  color: var(--ink-2);
  text-wrap: pretty;
}
.hero-cta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
  margin-top: 38px;
}
.hero-meta {
  margin-top: 18px;
  font-size: 13.5px;
  color: var(--ink-3);
  letter-spacing: 0.02em;
}
.hero-meta a {
  color: var(--green-700);
  text-decoration: underline;
  text-underline-offset: 3px;
}
.platform-hint {
  margin-top: 10px;
  font-size: 13.5px;
  color: var(--coral);
}
.hero-stage {
  margin-top: 76px;
  perspective: 2200px;
}

/* ---------- Window frame ---------- */
.window {
  position: relative;
  container-type: inline-size;
  border-radius: 14px;
  overflow: hidden;
  background: #fff;
  box-shadow: var(--shadow-lg);
}
.window img {
  display: block;
  width: 100%;
  height: auto;
}
.lights {
  position: absolute;
  left: 0.9cqw;
  top: 1.44cqw;
  display: flex;
  gap: 0.5cqw;
  transform: translateY(-50%);
}
.lights i {
  width: 0.78cqw;
  height: 0.78cqw;
  min-width: 6px;
  min-height: 6px;
  border-radius: 50%;
  background: #ff5f57;
  box-shadow: inset 0 0 0 0.5px rgba(0, 0, 0, 0.12);
}
.lights i:nth-child(2) {
  background: #febc2e;
}
.lights i:nth-child(3) {
  background: #28c840;
}
@supports (animation-timeline: view()) {
  @media (prefers-reduced-motion: no-preference) {
    .hero-window {
      transform-origin: 50% 0;
      animation: tilt linear both;
      animation-timeline: view();
      animation-range: entry 0% cover 40%;
    }
    @keyframes tilt {
      from {
        transform: rotateX(18deg) scale(0.92);
      }
      to {
        transform: none;
      }
    }
  }
}

/* 主图上的“手写批注”：像用页间的画笔在截图上圈画 */
.ink-layer {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}
.ink {
  fill: none;
  stroke: var(--pen);
  stroke-width: 3.4;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.ink-dash {
  stroke-width: 2.6;
  stroke-dasharray: 0.012 0.014;
}
.ink-text {
  font: 400 25px var(--hand);
  fill: var(--pen);
  letter-spacing: 0.04em;
}
.js .ink:not(.ink-dash) {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
}
.js .ink-dash,
.js .ink-text {
  opacity: 0;
}
.js .hero-window.is-inked .ink:not(.ink-dash) {
  animation: draw 0.8s var(--ease) forwards;
}
.js .hero-window.is-inked .ink:nth-of-type(3) {
  animation-delay: 1.05s;
}
.js .hero-window.is-inked .ink-dash {
  animation: fade 0.6s 0.55s var(--ease) forwards;
}
.js .hero-window.is-inked .ink-text {
  animation: fade 0.7s 1.2s var(--ease) forwards;
}
@keyframes fade {
  to {
    opacity: 1;
  }
}

/* ---------- Values ---------- */
.values {
  padding: 92px 0 104px;
}
.values-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px;
}
.value {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.value > .icon {
  font-size: 22px;
  margin-top: 3px;
  color: var(--green-600);
}
.value strong {
  display: block;
  font-size: 16px;
  font-weight: 600;
}
.value span {
  display: block;
  margin-top: 2px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink-3);
}

/* ---------- Video ---------- */
.film {
  padding: 0 0 128px;
}
.film-stage {
  position: relative;
  max-width: 1120px;
}
.film-frame {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #f8f1e2;
  border-radius: 22px;
  box-shadow: var(--shadow-lg);
}
.film-frame video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
/* 全屏后框跟着屏幕比例走，完整显示画面，不裁边 */
.film-frame video:fullscreen {
  object-fit: contain;
}
.film-play {
  display: none;
}
.js .film-play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: flex-end;
  padding: clamp(14px, 3.4%, 36px);
  font: inherit;
  text-align: left;
  background: none;
  border: 0;
  cursor: pointer;
}
.film-frame.is-playing .film-play {
  display: none;
}
.film-play-icon {
  display: grid;
  place-items: center;
  width: 56px;
  height: 56px;
  flex: none;
  color: #fdfbf5;
  font-size: 22px;
  background: linear-gradient(180deg, var(--green-500), var(--green-800));
  border-radius: 50%;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.2),
    0 10px 24px -8px rgba(21, 59, 51, 0.6);
  transition: transform 0.25s var(--ease);
}
.film-play-icon .icon {
  margin-left: 3px;
}
.film-play-text {
  display: grid;
  margin-left: -10px;
  padding: 10px 22px 10px 24px;
  line-height: 1.4;
  background: rgba(255, 253, 248, 0.94);
  border: 1px solid var(--line-2);
  border-left: 0;
  border-radius: 0 99px 99px 0;
  box-shadow: var(--shadow-sm);
}
.film-play-text b {
  font-size: 16px;
  color: var(--ink);
}
.film-play-text span {
  font-size: 13px;
  color: var(--ink-3);
}
.film-play:hover .film-play-icon {
  transform: scale(1.08);
}
.film-play:focus-visible {
  outline-offset: -6px;
  border-radius: 22px;
}
.film-note {
  position: absolute;
  right: 18px;
  top: -44px;
  font: 400 24px/1.4 var(--hand);
  color: var(--coral);
  letter-spacing: 0.04em;
  transform: rotate(4deg);
}
.film-note::after {
  /* 指向视频的小箭头 */
  content: '';
  position: absolute;
  right: -30px;
  top: 22px;
  width: 30px;
  height: 30px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cg fill='none' stroke='%23c1462f' stroke-width='1.8' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M3 4c12 0 20 8 21 21'/%3E%3Cpath d='M18 19.5l6 6 5-7'/%3E%3C/g%3E%3C/svg%3E")
    no-repeat center / contain;
}

/* ---------- Section scaffolding ---------- */
.section {
  padding: 140px 0;
}
.section-tint {
  background: var(--paper-2);
  box-shadow:
    inset 0 1px 0 rgba(22, 44, 38, 0.05),
    inset 0 -1px 0 rgba(22, 44, 38, 0.05);
}
.section-head {
  max-width: 760px;
}
.section-head.center {
  margin: 0 auto 64px;
  text-align: center;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font: 600 13px/1 var(--sans);
  letter-spacing: 0.2em;
  color: var(--green-600);
}
.eyebrow .icon {
  font-size: 15px;
  margin-right: -2px;
}
.eyebrow::before {
  content: '';
  width: 22px;
  height: 1.5px;
  background: currentColor;
  opacity: 0.6;
}
.section-head.center .eyebrow::after {
  content: '';
  width: 22px;
  height: 1.5px;
  background: currentColor;
  opacity: 0.6;
}
.section h2,
.dark h2,
.themes h2 {
  margin-top: 20px;
  font: 700 clamp(34px, 4.6vw, 58px) / 1.22 var(--serif);
  letter-spacing: 0.02em;
  text-wrap: balance;
}
.nb {
  display: inline-block;
}
.split-copy h2 {
  font-size: clamp(32px, 3.6vw, 46px);
}
.lead {
  margin-top: 22px;
  font-size: 17.5px;
  line-height: 1.95;
  color: var(--ink-2);
  text-wrap: pretty;
}
.section-head.center .lead {
  margin-inline: auto;
  max-width: 680px;
}
.fine {
  margin-top: 22px;
  font-size: 14px;
  color: var(--ink-3);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px 10px;
}
.split {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: 72px;
  align-items: center;
}
.checks {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 13px;
}
.checks li {
  position: relative;
  padding-left: 32px;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--ink-2);
}
.checks li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 3px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--green-100)
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2322594d' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M20 6 9 17l-5-5'/%3E%3C/svg%3E")
    no-repeat center / 12px;
}
.chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}
.chips li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 15px;
  font-size: 14px;
  color: var(--ink-2);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 99px;
}
.chips .icon {
  color: var(--green-600);
  font-size: 16px;
}

/* ---------- Dark band: AI ---------- */
.dark {
  position: relative;
  padding: 150px 0 156px;
  color: var(--night-ink-2);
  background: var(--night);
  overflow: hidden;
  isolation: isolate;
}
.dark h2,
.dark h3 {
  color: var(--night-ink);
}
.dark .lead {
  color: var(--night-ink-2);
}
.dark .eyebrow {
  color: var(--violet-soft);
}
.dark kbd {
  color: var(--night-ink);
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.18);
}
.ai-aurora {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(ellipse 55% 40% at 18% 0%, rgba(61, 133, 116, 0.42), transparent 70%),
    radial-gradient(ellipse 45% 36% at 86% 6%, rgba(106, 90, 224, 0.34), transparent 70%),
    radial-gradient(ellipse 50% 30% at 50% 100%, rgba(226, 187, 99, 0.12), transparent 70%),
    linear-gradient(180deg, #0d1916, var(--night) 40%, #0a110f);
}
.ai-aurora::after {
  /* 细网格，像笔记本的底纹 */
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 48px 48px;
  -webkit-mask-image: radial-gradient(ellipse 70% 50% at 50% 0%, #000, transparent 80%);
  mask-image: radial-gradient(ellipse 70% 50% at 50% 0%, #000, transparent 80%);
}
.ai-head h2 {
  font-size: clamp(42px, 6.4vw, 88px);
  letter-spacing: 0.01em;
}
.ai-heading-mark {
  font-family: var(--sans);
  color: var(--violet-soft);
}
.ai-capabilities {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 12px 28px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
  color: var(--night-ink);
  font-size: clamp(16px, 1.6vw, 20px);
  line-height: 1.5;
}
.ai-capabilities li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.ai-capabilities .icon {
  color: var(--violet-soft);
}
.ai-head .lead {
  margin-top: 18px;
}
.ai-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 20px;
}
.span-5 {
  grid-column: span 5;
}
.span-6 {
  grid-column: span 6;
}
.span-7 {
  grid-column: span 7;
}
.ai-tile {
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  overflow: hidden;
  background:
    radial-gradient(ellipse 80% 60% at 0% 0%, rgba(255, 255, 255, 0.05), transparent 70%),
    rgba(255, 255, 255, 0.03);
  border: 1px solid var(--night-line);
  border-radius: 22px;
  transition:
    border-color 0.3s,
    transform 0.3s var(--ease);
}
.ai-tile:hover {
  border-color: rgba(185, 173, 255, 0.28);
}
.ai-copy {
  padding: 34px 36px 26px;
}
.ai-copy h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  font: 700 22px/1.35 var(--serif);
  letter-spacing: 0.03em;
}
.ai-copy h3 .icon {
  font-size: 20px;
  color: var(--violet-soft);
}
.ai-copy p {
  margin-top: 12px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--night-ink-2);
}
.kinds {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}
.kinds li {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 11px 4px 9px;
  font-size: 13px;
  color: var(--night-ink);
  background: color-mix(in srgb, var(--c) 18%, transparent);
  border: 1px solid color-mix(in srgb, var(--c) 45%, transparent);
  border-radius: 99px;
}
.kinds li::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--c);
}
.ai-shot {
  margin: auto 0 0 36px;
}
.ai-shot img {
  display: block;
  width: 100%;
  border-radius: 12px 0 0 0;
  box-shadow:
    0 0 0 1px rgba(255, 255, 255, 0.08),
    -16px -10px 48px -24px rgba(0, 0, 0, 0.8);
}
.shot-tall {
  margin-right: 36px;
}
.shot-tall img {
  border-radius: 12px 12px 0 0;
}
.shot-ask img {
  max-width: 400px;
  margin-inline: auto;
}
.agent {
  display: grid;
  gap: 10px;
  margin: auto 36px 36px;
}
.agent-step {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 14px;
  font-size: 14px;
  color: var(--night-ink-2);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--night-line);
  border-radius: 12px;
}
.agent-step b {
  font-weight: 600;
  color: var(--night-ink);
}
.agent-step .icon {
  font-size: 16px;
  color: var(--violet-soft);
}
.agent-step.done .icon {
  color: #7fd0b8;
}
.agent-step > span {
  margin-left: auto;
  font-size: 12.5px;
  color: var(--night-ink-3);
}
.agent-actions {
  display: flex;
  gap: 6px;
}
.agent-actions i {
  font-style: normal;
  padding: 3px 10px;
  font-size: 12.5px;
  color: var(--night-ink-2);
  border: 1px solid var(--night-line);
  border-radius: 7px;
}
.agent-actions i.primary {
  color: #fff;
  background: var(--violet);
  border-color: transparent;
}
.agent-step:not(.done) {
  border-color: rgba(185, 173, 255, 0.22);
  background: rgba(106, 90, 224, 0.08);
}

/* 找论文：横跨整行，左边说明，右边对话 */
.ai-wide {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  align-items: center;
}
.ai-wide .ai-copy {
  padding: 40px 16px 40px 40px;
}
.ai-wide .agent {
  margin: 36px 36px 36px 0;
}
.tag-new {
  margin-left: 2px;
  padding: 2px 9px;
  white-space: nowrap;
  font: 600 12px/1.5 var(--sans);
  letter-spacing: 0.02em;
  color: #fff;
  background: linear-gradient(120deg, var(--green-600), var(--violet));
  border-radius: 99px;
}
.dark .checks {
  margin-top: 22px;
  gap: 10px;
}
.dark .checks li {
  font-size: 14.5px;
  color: var(--night-ink-2);
}
.dark .checks li::before {
  background-color: rgba(127, 208, 184, 0.14);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%237fd0b8' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M20 6 9 17l-5-5'/%3E%3C/svg%3E");
}
.agent-ask {
  justify-self: end;
  max-width: 88%;
  margin-bottom: 4px;
  padding: 10px 15px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--night-ink);
  background: rgba(106, 90, 224, 0.24);
  border-radius: 14px 14px 4px 14px;
}
.papers {
  display: grid;
  gap: 2px;
  margin: 0 0 0 26px;
  padding: 6px;
  list-style: none;
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--night-line);
  border-radius: 12px;
}
.papers li {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  column-gap: 12px;
  padding: 7px 10px;
  line-height: 1.5;
}
.papers b {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--night-ink);
}
.papers span {
  font-size: 12px;
  color: var(--night-ink-3);
}
.papers em {
  grid-area: 1 / 2 / 3;
  align-self: center;
  padding: 1px 8px;
  font: 600 11.5px/1.6 var(--sans);
  color: #7fd0b8;
  border: 1px solid rgba(127, 208, 184, 0.35);
  border-radius: 6px;
}

/* ---------- Whiteboard ---------- */
.board {
  position: relative;
  isolation: isolate;
  overflow: hidden;
}
.board::before {
  /* 白板的点阵 */
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: radial-gradient(rgba(34, 89, 77, 0.16) 1.2px, transparent 1.4px);
  background-size: 26px 26px;
  -webkit-mask-image: radial-gradient(ellipse 70% 55% at 50% 42%, #000 30%, transparent 75%);
  mask-image: radial-gradient(ellipse 70% 55% at 50% 42%, #000 30%, transparent 75%);
}
.board .eyebrow {
  color: var(--violet);
}
.board-stage {
  position: relative;
  width: min(960px, 100% - 48px);
  margin-inline: auto;
}
.board-frame {
  border-radius: 16px;
  overflow: hidden;
  background: #fbfaf7;
  box-shadow:
    0 0 0 1px rgba(22, 44, 38, 0.08),
    0 30px 60px -20px rgba(22, 52, 44, 0.3),
    0 80px 140px -60px rgba(106, 90, 224, 0.35);
}
.board-frame img {
  display: block;
  width: 100%;
}
.callout {
  position: absolute;
  white-space: nowrap;
  font: 400 21px/1.45 var(--hand);
  color: var(--coral);
  letter-spacing: 0.03em;
}
.callout::after {
  content: '';
  position: absolute;
  top: 50%;
  width: 54px;
  height: 22px;
  margin-top: -11px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 54 22'%3E%3Cg fill='none' stroke='%23c1462f' stroke-width='1.8' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M2 14C16 4 34 4 50 12'/%3E%3Cpath d='M42 5l8 7-9 4'/%3E%3C/g%3E%3C/svg%3E")
    no-repeat center / contain;
}
.callout.c1,
.callout.c3 {
  left: calc(100% + 60px);
  text-align: left;
}
.callout.c1::after,
.callout.c3::after {
  right: calc(100% + 6px);
  transform: scaleX(-1);
}
.callout.c2 {
  right: calc(100% + 60px);
  text-align: right;
}
.callout.c2::after {
  left: calc(100% + 6px);
}
.callout.c1 {
  top: 17%;
  transform: rotate(-4deg);
}
.callout.c2 {
  top: 45%;
  transform: rotate(3deg);
}
.callout.c3 {
  top: 66%;
  transform: rotate(-3deg);
}
.modes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 72px;
}
.mode {
  padding: 30px 30px 32px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition:
    transform 0.25s var(--ease),
    box-shadow 0.25s var(--ease);
}
.mode:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 40px -20px rgba(22, 52, 44, 0.3);
}
.mode-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  font-size: 21px;
  color: var(--violet);
  background: rgba(106, 90, 224, 0.09);
  border-radius: 12px;
}
.mode h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 20px;
  font: 700 21px/1.35 var(--serif);
  letter-spacing: 0.03em;
}
.mode h3 small {
  font: 600 11.5px/1 var(--sans);
  letter-spacing: 0.04em;
  padding: 4px 8px;
  color: var(--ink-2);
  background: var(--paper-2);
  border-radius: 6px;
}
.mode p {
  margin-top: 10px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}
.board-chips {
  margin-top: 36px;
}
.board-chips .icon {
  color: var(--violet);
}

/* ---------- Models ---------- */
.models .eyebrow {
  color: var(--green-600);
}
.model-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(0, 1fr) minmax(0, 1fr);
  gap: 20px;
}
.model-card {
  display: flex;
  flex-direction: column;
  padding: 32px 30px 30px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.model-icon {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  font-size: 21px;
  color: var(--green-700);
  background: var(--green-100);
  border-radius: 12px;
}
.model-card h3 {
  margin-top: 20px;
  font: 700 21px/1.35 var(--serif);
  letter-spacing: 0.03em;
}
.model-card p {
  margin-top: 10px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}
.providers {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: auto 0 0;
  padding: 24px 0 0;
  list-style: none;
}
.providers li {
  padding: 6px 13px;
  font: 600 13.5px/1.3 var(--sans);
  color: var(--ink);
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 9px;
}
.providers li.more {
  font-weight: 500;
  color: var(--ink-3);
  background: none;
  border-style: dashed;
}
.facts {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid var(--line-2);
}
.fact {
  display: flex;
  gap: 14px;
  align-items: flex-start;
}
.fact > .icon {
  font-size: 21px;
  margin-top: 3px;
  color: var(--green-600);
}
.fact strong {
  display: block;
  font-size: 16px;
  font-weight: 600;
}
.fact span {
  display: block;
  margin-top: 4px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-3);
}

/* ---------- Themes：区块颜色跟着选中的主题变 ---------- */
.themes {
  --t-bg: #12161c;
  --t-ink: var(--ink);
  --t-ink-2: var(--ink-2);
  --t-line: rgba(22, 44, 38, 0.1);
  --t-a: #5ec2b1;
  position: relative;
  padding: 140px 0 120px;
  color: var(--t-ink-2);
  background: var(--t-bg);
  isolation: isolate;
  overflow: hidden;
  transition:
    background-color 1s var(--ease),
    color 1s var(--ease);
}
.themes[data-tone='dark'] {
  --t-ink: #f3f1ea;
  --t-ink-2: rgba(240, 238, 230, 0.72);
  --t-line: rgba(255, 255, 255, 0.12);
}
.themes h2 {
  color: var(--t-ink);
  transition: color 0.8s var(--ease);
}
.themes .lead {
  color: var(--t-ink-2);
}
.themes .eyebrow {
  color: var(--t-a);
  transition: color 0.8s var(--ease);
}
.themes-glow {
  position: absolute;
  left: 50%;
  top: 46%;
  z-index: -1;
  width: min(1500px, 150vw);
  aspect-ratio: 1.8;
  transform: translateX(-50%);
  background: radial-gradient(closest-side, var(--t-a), transparent);
  opacity: 0.2;
  filter: blur(40px);
  transition: background 0.8s var(--ease);
}
.themes[data-tone='dark'] .themes-glow {
  opacity: 0.28;
}
.theme-picker {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 10px;
  max-width: 900px;
  margin: -16px auto 0;
}
.theme-picker button {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-rows: auto auto;
  column-gap: 11px;
  align-items: center;
  padding: 11px 14px;
  text-align: left;
  font: inherit;
  color: var(--t-ink);
  background: color-mix(in srgb, var(--t-bg) 70%, rgba(255, 255, 255, 0.5));
  border: 1px solid var(--t-line);
  border-radius: 14px;
  cursor: pointer;
  transition:
    border-color 0.25s,
    background-color 0.6s,
    color 0.6s,
    transform 0.2s var(--ease),
    box-shadow 0.25s;
}
.themes[data-tone='dark'] .theme-picker button {
  background: rgba(255, 255, 255, 0.04);
}
.theme-picker button:hover {
  transform: translateY(-1px);
  border-color: color-mix(in srgb, var(--a) 60%, transparent);
}
.theme-picker button[aria-selected='true'] {
  border-color: var(--a);
  box-shadow:
    0 0 0 1px var(--a),
    0 10px 24px -14px var(--a);
}
.theme-picker i {
  grid-row: span 2;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--b) 0 50%, var(--a) 50% 100%);
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.14);
}
.theme-picker button[data-bold] i {
  border-radius: 8px;
}
.theme-picker b {
  font: 700 15.5px/1.3 var(--serif);
  letter-spacing: 0.04em;
}
.theme-picker span {
  font-size: 12px;
  line-height: 1.4;
  color: var(--t-ink-2);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.theme-stage {
  margin-top: 56px;
}
.theme-window {
  background: var(--t-bg);
  transition: box-shadow 0.8s;
}
.themes[data-tone='dark'] .theme-window {
  box-shadow:
    0 0 0 1px rgba(255, 255, 255, 0.08),
    0 40px 100px -30px rgba(0, 0, 0, 0.7);
}
.theme-window img {
  transition: opacity 0.45s var(--ease);
}
.theme-window img.next {
  position: absolute;
  inset: 0;
  opacity: 0;
}
.theme-window img.next.on {
  opacity: 1;
}
.theme-note {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 26px;
  font-size: 14.5px;
  color: var(--t-ink-2);
}
.theme-note .icon {
  font-size: 17px;
  color: var(--t-a);
}
.js .theme-picker:not(.is-ready) {
  visibility: hidden;
}

/* ---------- Reading ---------- */
.tabs {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 4px;
  width: max-content;
  max-width: 100%;
  margin: -12px auto 48px;
  padding: 5px;
  background: var(--paper-2);
  border: 1px solid var(--line);
  border-radius: 14px;
}
.tabs button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  font: 600 15px/1.2 var(--sans);
  color: var(--ink-3);
  background: none;
  border: 0;
  border-radius: 10px;
  cursor: pointer;
  transition:
    background-color 0.2s,
    color 0.2s,
    box-shadow 0.2s;
}
.tabs button .icon {
  font-size: 17px;
}
.tabs button:hover {
  color: var(--ink);
}
.tabs button[aria-selected='true'] {
  color: var(--green-800);
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.panel {
  display: grid;
  grid-template-columns: minmax(0, 0.78fr) minmax(0, 1.22fr);
  gap: 64px;
  align-items: center;
}
.panel[hidden] {
  display: none;
}
.js .panel:not([hidden]) {
  animation: panel-in 0.5s var(--ease);
}
@keyframes panel-in {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
}
.panel-copy h3 {
  font: 700 clamp(28px, 3vw, 38px) / 1.3 var(--serif);
  letter-spacing: 0.02em;
}
.panel-copy > p {
  margin-top: 18px;
  font-size: 16.5px;
  line-height: 1.95;
  color: var(--ink-2);
}
.panel-shot {
  border-radius: 14px;
  overflow: hidden;
  background: var(--card);
  box-shadow: var(--shadow-lg);
}
.panel-shot img {
  display: block;
  width: 100%;
}
.tools {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}
.tools li {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 13px 4px 10px;
  font-size: 12.5px;
  color: var(--ink-2);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
}
.tools .icon {
  font-size: 20px;
  color: var(--green-700);
}
.swatches {
  display: inline-flex;
  gap: 5px;
}
.swatches i {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--c);
  box-shadow: inset 0 0 0 1px rgba(0, 0, 0, 0.1);
}
.details {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 96px;
}
.detail {
  padding: 28px 28px 30px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  transition:
    transform 0.25s var(--ease),
    box-shadow 0.25s var(--ease);
}
.detail:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 40px -20px rgba(22, 52, 44, 0.3);
}
.detail > .icon {
  font-size: 23px;
  color: var(--green-600);
}
.detail h3 {
  margin-top: 14px;
  font: 700 19px/1.35 var(--serif);
  letter-spacing: 0.03em;
}
.detail p {
  margin-top: 8px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--ink-2);
}

/* ---------- Privacy tree ---------- */
.tree {
  background: #1a2521;
  color: #d9dfd9;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}
.tree-head {
  position: relative;
  display: flex;
  justify-content: center;
  padding: 13px 16px;
  font-size: 13px;
  color: rgba(217, 223, 217, 0.6);
  background: rgba(255, 255, 255, 0.04);
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}
.tree-head .lights {
  left: 16px;
  top: 50%;
  gap: 7px;
}
.tree-head .lights i {
  width: 11px;
  height: 11px;
}
.tree pre {
  margin: 0;
  padding: 28px 30px 32px;
  font: 14px/2 var(--mono);
  overflow-x: auto;
}
.t-dir {
  color: #e8c877;
}
.t-file {
  color: #eef2ee;
}
.t-hidden {
  color: #7fd0b8;
  font-weight: 600;
}
.t-dim {
  color: rgba(217, 223, 217, 0.45);
}
.t-hand {
  font: 17px/1 var(--hand);
  color: #f08e72;
}

/* ---------- Download ---------- */
.download {
  padding-top: 150px;
}
.download-card {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 84px 32px 48px;
  color: #ebe5d7;
  border-radius: 32px;
  overflow: hidden;
  isolation: isolate;
  background:
    radial-gradient(ellipse 70% 60% at 50% 0%, rgba(61, 133, 116, 0.6), transparent 70%),
    radial-gradient(ellipse 40% 50% at 100% 100%, rgba(226, 187, 99, 0.18), transparent 70%),
    radial-gradient(ellipse 40% 50% at 0% 100%, rgba(106, 90, 224, 0.12), transparent 70%),
    linear-gradient(180deg, var(--green-800), var(--green-950));
  box-shadow: 0 40px 80px -40px rgba(15, 46, 40, 0.6);
}
.download-card::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: repeating-linear-gradient(
    to bottom,
    transparent 0 39px,
    rgba(255, 255, 255, 0.035) 39px 40px
  );
  -webkit-mask-image: linear-gradient(#000, transparent 80%);
  mask-image: linear-gradient(#000, transparent 80%);
}
.download-icon {
  width: 104px;
  height: 104px;
  filter: drop-shadow(0 16px 24px rgba(0, 0, 0, 0.35));
}
.download-card h2 {
  margin-top: 26px;
  color: #fbf7ec;
}
.download-card .lead {
  margin-top: 12px;
  color: rgba(235, 229, 215, 0.75);
}
.download-options {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px 18px;
  margin-top: 36px;
}
.download-option {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.download-option .btn {
  min-width: 230px;
}
.download-file {
  font-size: 12.5px;
  letter-spacing: 0.04em;
  color: rgba(235, 229, 215, 0.55);
}
.specs {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0;
  margin: 46px 0 0;
  padding-top: 28px;
  border-top: 1px solid rgba(235, 229, 215, 0.14);
  width: min(760px, 100%);
}
.specs div {
  flex: 1 1 150px;
  padding: 4px 16px;
}
.specs div + div {
  border-left: 1px solid rgba(235, 229, 215, 0.14);
}
.specs dt {
  font-size: 12.5px;
  letter-spacing: 0.14em;
  color: rgba(235, 229, 215, 0.55);
}
.specs dd {
  margin: 6px 0 0;
  font-size: 15px;
  color: #fbf7ec;
}
.install {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  margin-top: 24px;
}
.install-col {
  padding: 36px 36px 34px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 22px;
}
.install-col h3 {
  font: 700 22px/1.3 var(--serif);
  letter-spacing: 0.03em;
}
.install-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
/* Without scripts both systems' steps are shown, each under its own title. */
.os-switch {
  display: none;
  padding: 3px;
  background: var(--paper-2);
  border: 1px solid var(--line);
  border-radius: 10px;
}
.js .os-switch {
  display: flex;
}
.os-switch button {
  padding: 6px 14px;
  font: 600 13.5px/1.2 var(--sans);
  color: var(--ink-3);
  background: none;
  border: 0;
  border-radius: 7px;
  cursor: pointer;
  transition:
    background-color 0.2s,
    color 0.2s;
}
.os-switch button:hover {
  color: var(--ink);
}
.os-switch button[aria-selected='true'] {
  color: var(--green-900);
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.os-panel-title {
  margin-top: 24px;
  font-weight: 600;
  color: var(--ink-2);
}
.js .os-panel-title {
  display: none;
}
.steps {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 20px;
}
.steps li {
  display: flex;
  gap: 16px;
}
.step-n {
  flex: none;
  display: grid;
  place-items: center;
  width: 30px;
  height: 30px;
  font: 700 15px/1 var(--latin);
  color: var(--green-800);
  background: var(--green-100);
  border-radius: 50%;
}
.steps strong {
  display: block;
  font-weight: 600;
}
.steps div span {
  display: block;
  margin-top: 2px;
  font-size: 14.5px;
  color: var(--ink-3);
  line-height: 1.7;
}
.notice {
  margin-top: 28px;
  background: #fbf3e2;
  border: 1px solid #efdcb4;
  border-radius: 14px;
}
.notice summary {
  position: relative;
  padding: 14px 44px 14px 18px;
  font-size: 14.5px;
  font-weight: 600;
  color: #7b5516;
}
.notice-body {
  padding: 0 18px 16px;
  font-size: 14px;
  line-height: 1.8;
  color: #6c5530;
  display: grid;
  gap: 10px;
}
.notice-body a {
  color: #8c5d10;
  text-decoration: underline;
  text-underline-offset: 3px;
}
.changes {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 14px;
}
.changes li {
  position: relative;
  padding-left: 18px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-3);
}
.changes li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--gold);
}
.changes strong {
  display: block;
  font-weight: 600;
  color: var(--ink);
}
.install-col .fine {
  margin-top: 24px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

/* ---------- Details / FAQ ---------- */
details summary {
  cursor: pointer;
  list-style: none;
}
details summary::-webkit-details-marker {
  display: none;
}
.faq {
  display: grid;
  grid-template-columns: minmax(0, 0.7fr) minmax(0, 1.3fr);
  gap: 64px;
  align-items: start;
}
.faq .section-head {
  position: sticky;
  top: 120px;
}
.faq-list {
  border-top: 1px solid var(--line-2);
}
.faq-list details {
  border-bottom: 1px solid var(--line-2);
}
.faq-list summary {
  position: relative;
  padding: 24px 48px 24px 0;
  font: 600 17.5px/1.5 var(--sans);
  color: var(--ink);
  transition: color 0.2s;
}
.faq-list summary:hover {
  color: var(--green-700);
}
.faq-list summary::after,
.notice summary::after {
  content: '';
  position: absolute;
  right: 6px;
  top: 50%;
  width: 18px;
  height: 18px;
  margin-top: -9px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%237a817c' stroke-width='2' stroke-linecap='round'%3E%3Cpath d='M5 12h14M12 5v14'/%3E%3C/svg%3E")
    no-repeat center / contain;
  transition: transform 0.3s var(--ease);
}
.faq-list details[open] summary::after,
.notice[open] summary::after {
  transform: rotate(45deg);
}
.notice summary::after {
  right: 14px;
  width: 16px;
  height: 16px;
  margin-top: -8px;
  filter: sepia(1) saturate(3) hue-rotate(-10deg);
}
.faq-list details p {
  padding: 0 48px 26px 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--ink-2);
}

/* ---------- Footer ---------- */
.footer {
  padding: 64px 0 40px;
  border-top: 1px solid var(--line);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 32px;
  flex-wrap: wrap;
}
.footer-brand p {
  margin-top: 14px;
  font: 400 17px/1.6 var(--hand);
  color: var(--ink-3);
  letter-spacing: 0.06em;
}
.footer-links {
  display: flex;
  gap: 28px;
  flex-wrap: wrap;
}
.footer-links a {
  font-size: 14.5px;
  color: var(--ink-2);
}
.footer-links a:hover {
  color: var(--ink);
}
.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin-top: 44px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--ink-3);
}
.footer-legal a {
  color: var(--ink-3);
}
.footer-legal a:hover {
  color: var(--ink-2);
}

/* ---------- Toast ---------- */
.toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  z-index: 60;
  display: flex;
  align-items: center;
  gap: 12px;
  max-width: calc(100% - 32px);
  padding: 13px 18px;
  font-size: 14.5px;
  color: #f4efe3;
  background: rgba(21, 36, 32, 0.94);
  border-radius: 14px;
  box-shadow: 0 20px 40px -12px rgba(0, 0, 0, 0.45);
  transform: translate(-50%, 24px);
  opacity: 0;
  pointer-events: none;
  transition:
    opacity 0.3s,
    transform 0.35s var(--ease);
}
.toast.is-on {
  opacity: 1;
  transform: translate(-50%, 0);
  pointer-events: auto;
}
.toast a {
  color: var(--gold);
  white-space: nowrap;
}

/* ---------- Reveal ---------- */
.js .reveal {
  opacity: 0;
  transform: translateY(28px);
  transition:
    opacity 0.9s var(--ease),
    transform 0.9s var(--ease);
  transition-delay: var(--d, 0s);
}
.js .reveal.in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .js .reveal,
  .js .hand-note {
    opacity: 1;
    transform: none;
    transition: none;
    animation: none;
  }
  .js .hand-note {
    transform: rotate(-6deg);
  }
  .js .mark {
    background-size: 100% 100%;
    animation: none;
  }
  .js .hand-note path,
  .js .ink:not(.ink-dash) {
    stroke-dashoffset: 0;
    animation: none;
  }
  .js .ink-dash,
  .js .ink-text {
    opacity: 1;
    animation: none;
  }
  .js .panel:not([hidden]) {
    animation: none;
  }
}

/* ---------- Responsive ---------- */
@media (max-width: 1339px) {
  .hand-note {
    display: none;
  }
}
@media (max-width: 1379px) {
  .callout {
    display: none;
  }
}
@media (max-width: 1000px) {
  .nav-links {
    display: none;
  }
  .nav-inner > .btn {
    margin-left: auto;
  }
  .values-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 28px 32px;
  }
  .ai-grid > * {
    grid-column: 1 / -1;
  }
  .ai-wide {
    grid-template-columns: 1fr;
  }
  .ai-wide .ai-copy {
    padding: 34px 36px 8px;
  }
  .ai-wide .agent {
    margin: 20px 36px 36px;
  }
  .shot-tall img {
    max-width: 520px;
    margin-inline: auto;
  }
  .modes,
  .model-grid,
  .facts {
    grid-template-columns: 1fr;
  }
  .modes {
    max-width: 620px;
    margin-inline: auto;
  }
  .facts {
    gap: 22px;
  }
  .theme-picker {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
  .theme-picker button {
    grid-template-columns: 1fr;
    justify-items: center;
    row-gap: 6px;
    padding: 12px 6px;
    text-align: center;
  }
  .theme-picker i {
    grid-row: auto;
  }
  .theme-picker span {
    display: none;
  }
  .panel,
  .split,
  .faq {
    grid-template-columns: 1fr;
    gap: 40px;
  }
  .panel-copy {
    max-width: 640px;
  }
  .details {
    grid-template-columns: repeat(2, 1fr);
  }
  .faq .section-head {
    position: static;
  }
  .install {
    grid-template-columns: 1fr;
  }
}
@media (max-width: 640px) {
  body {
    font-size: 15px;
  }
  .container,
  .container-wide,
  .board-stage {
    width: calc(100% - 32px);
  }
  .nav-inner {
    height: 60px;
    gap: 12px;
  }
  .hero {
    padding-top: 112px;
  }
  .hero-title {
    font-size: clamp(44px, 13vw, 56px);
  }
  .hero-cta {
    flex-direction: column;
    align-self: stretch;
    gap: 10px;
  }
  .hero-cta .btn {
    width: 100%;
  }
  .hero-stage {
    margin-top: 48px;
  }
  .ink-layer {
    display: none;
  }
  .window {
    border-radius: 9px;
  }
  .values {
    padding: 64px 0;
  }
  .values-grid {
    grid-template-columns: 1fr;
    gap: 22px;
  }
  .section,
  .themes {
    padding: 92px 0;
  }
  .dark {
    padding: 96px 0;
  }
  .section-head.center {
    margin-bottom: 44px;
  }
  .ai-capabilities {
    display: grid;
    grid-template-columns: repeat(2, max-content);
    gap: 12px 24px;
    margin-top: 24px;
  }
  .ai-grid {
    gap: 14px;
  }
  .ai-copy {
    padding: 26px 24px 20px;
  }
  .ai-shot {
    margin-left: 24px;
  }
  .shot-tall {
    margin-right: 24px;
  }
  .agent,
  .ai-wide .agent {
    margin: 4px 20px 24px;
  }
  .ai-wide .ai-copy {
    padding: 26px 24px 8px;
  }
  .papers {
    margin-left: 0;
  }
  .film {
    padding-bottom: 92px;
  }
  .film-frame {
    border-radius: 12px;
  }
  .film-play-icon {
    width: 44px;
    height: 44px;
    font-size: 18px;
  }
  .film-play-text {
    /* 小屏只留圆形播放键，免得挡住画面；文字留给读屏 */
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
  }
  .film-note {
    display: none;
  }
  .agent-step {
    flex-wrap: wrap;
    font-size: 13.5px;
  }
  .board-frame {
    border-radius: 10px;
  }
  .modes {
    margin-top: 48px;
  }
  .mode,
  .model-card {
    padding: 26px 24px;
  }
  .theme-picker {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
  }
  .theme-picker button {
    padding: 10px 2px;
    border-radius: 11px;
  }
  .theme-picker b {
    font-size: 13px;
    letter-spacing: 0;
  }
  .theme-picker i {
    width: 24px;
    height: 24px;
  }
  .theme-stage {
    margin-top: 32px;
  }
  .tabs {
    width: 100%;
    flex-wrap: nowrap;
    overflow-x: auto;
    justify-content: flex-start;
    scrollbar-width: none;
  }
  .tabs button {
    flex: 1 0 auto;
    justify-content: center;
    padding: 9px 10px;
    font-size: 14px;
  }
  .tabs button .icon {
    display: none;
  }
  .tools {
    gap: 6px;
  }
  .tools li {
    font-size: 11.5px;
    padding: 11px 2px 8px;
  }
  .details {
    grid-template-columns: 1fr;
    gap: 12px;
    margin-top: 64px;
  }
  .detail {
    padding: 22px 22px 24px;
  }
  .panel-shot,
  .window,
  .tree {
    box-shadow:
      0 0 0 1px rgba(22, 44, 38, 0.07),
      0 16px 32px -12px rgba(22, 52, 44, 0.28);
  }
  .download {
    padding-top: 92px;
  }
  .download-card {
    padding: 56px 20px 28px;
    border-radius: 22px;
  }
  .download-options,
  .download-option,
  .download-option .btn {
    width: 100%;
  }
  .specs div {
    flex-basis: 50%;
    padding: 10px 12px;
  }
  .specs div + div {
    border-left: 0;
  }
  .install-col {
    padding: 28px 22px;
  }
  .faq-list summary {
    font-size: 16.5px;
    padding-right: 36px;
  }
  .faq-list details p {
    padding-right: 8px;
  }
  .tree pre {
    padding: 22px 20px 26px;
    font-size: 12.5px;
  }
  .footer-legal {
    margin-top: 32px;
  }
}
@media (max-width: 400px) {
  .xy-crumb {
    gap: 6px;
  }
  .xy-home,
  .xy-sep {
    font-size: 13px;
  }
}