/* ============================================================
   考拉的个人站 · 样式表
   纯手写 CSS，零第三方依赖。
   改配色只需改下面 :root 里的变量。
   ============================================================ */

/* ---------- 设计变量 ---------- */
:root {
  --a1: #22d3ee;   /* 青 */
  --a2: #818cf8;   /* 靛 */
  --a3: #c084fc;   /* 紫 */
  --grad: linear-gradient(115deg, var(--a1) 0%, var(--a2) 48%, var(--a3) 100%);
  --grad-soft: linear-gradient(115deg, rgba(34,211,238,.16), rgba(129,140,248,.16) 48%, rgba(192,132,252,.16));

  --wrap: 1080px;
  --pad: 24px;
  --r-lg: 20px;
  --r-md: 14px;
  --r-sm: 10px;

  --ease: cubic-bezier(.22, .61, .36, 1);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
          "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

/* 深色（默认） */
[data-theme="dark"] {
  --bg: #07080c;
  --surface: rgba(255,255,255,.038);
  --surface-2: rgba(255,255,255,.062);
  --border: rgba(255,255,255,.09);
  --border-2: rgba(255,255,255,.17);
  --text: #e9edf5;
  --text-2: #a4aec0;
  --text-3: #6a7488;
  --shadow: 0 24px 60px -28px rgba(0,0,0,.9);
  --grid-line: rgba(255,255,255,.035);
  --orb: .55;
  color-scheme: dark;
}

/* 浅色 */
[data-theme="light"] {
  --bg: #f5f6fa;
  --surface: #ffffff;
  --surface-2: #ffffff;
  --border: rgba(15,23,42,.10);
  --border-2: rgba(15,23,42,.20);
  --text: #0d1526;
  --text-2: #4a5568;
  --text-3: #8b95a7;
  --shadow: 0 22px 48px -30px rgba(15,23,42,.45);
  --grid-line: rgba(15,23,42,.045);
  --orb: .3;
  color-scheme: light;
}

/* ---------- 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 96px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color .4s var(--ease), color .4s var(--ease);
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
ul, ol, dl, dd { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, p { margin: 0; }

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* 图标统一规格 */
.ico {
  width: 1.15em; height: 1.15em;
  flex: none;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.skip-link {
  position: fixed; top: -100px; left: 16px; z-index: 200;
  padding: 10px 16px; border-radius: var(--r-sm);
  background: var(--a2); color: #fff;
  transition: top .2s;
}
.skip-link:focus { top: 16px; }

:focus-visible {
  outline: 2px solid var(--a1);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- 背景装饰 ---------- */
.bg { position: fixed; inset: 0; z-index: -1; overflow: hidden; pointer-events: none; }

.bg__orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  opacity: var(--orb);
  transition: opacity .5s var(--ease);
}
.bg__orb--1 {
  width: 46vw; height: 46vw; min-width: 340px; min-height: 340px;
  top: -14vw; left: -10vw;
  background: radial-gradient(circle, rgba(34,211,238,.85), transparent 68%);
  animation: drift1 26s ease-in-out infinite;
}
.bg__orb--2 {
  width: 40vw; height: 40vw; min-width: 300px; min-height: 300px;
  top: 8vh; right: -12vw;
  background: radial-gradient(circle, rgba(168,85,247,.8), transparent 68%);
  animation: drift2 32s ease-in-out infinite;
}
.bg__orb--3 {
  width: 52vw; height: 52vw; min-width: 360px; min-height: 360px;
  bottom: -22vw; left: 24vw;
  background: radial-gradient(circle, rgba(129,140,248,.7), transparent 70%);
  animation: drift3 38s ease-in-out infinite;
}

@keyframes drift1 { 50% { transform: translate3d(6vw, 5vh, 0) scale(1.12); } }
@keyframes drift2 { 50% { transform: translate3d(-7vw, 7vh, 0) scale(1.08); } }
@keyframes drift3 { 50% { transform: translate3d(4vw, -6vh, 0) scale(1.14); } }

.bg__grid {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 62px 62px;
  mask-image: radial-gradient(ellipse 78% 62% at 50% 34%, #000 25%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 78% 62% at 50% 34%, #000 25%, transparent 78%);
  transition: background-image .4s var(--ease);
}
.bg__vignette {
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 100% 70% at 50% 0%, transparent 40%, var(--bg) 100%);
  opacity: .72;
}

/* ---------- 导航 ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  background: color-mix(in srgb, var(--bg) 72%, transparent);
  border-bottom: 1px solid transparent;
  transition: border-color .3s, background-color .3s;
}
.nav.is-stuck { border-bottom-color: var(--border); }

.nav__inner {
  display: flex; align-items: center; gap: 20px;
  height: 66px;
}

.nav__brand {
  display: inline-flex; align-items: center; gap: 9px;
  font-weight: 650; letter-spacing: .02em; white-space: nowrap;
}
.nav__dot {
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--grad);
  box-shadow: 0 0 0 3px rgba(129,140,248,.16);
}
.nav__brand-text em { font-style: normal; color: var(--text-3); font-weight: 500; }

.nav__links {
  display: flex; align-items: center; gap: 4px;
  margin-left: auto;
}
.nav__links a {
  position: relative;
  padding: 7px 13px;
  font-size: 14.5px;
  color: var(--text-2);
  border-radius: 999px;
  transition: color .2s, background-color .2s;
}
.nav__links a:hover { color: var(--text); background: var(--surface-2); }
.nav__links a.is-active { color: var(--text); }
.nav__links a.is-active::after {
  content: ""; position: absolute; left: 50%; bottom: 1px;
  width: 16px; height: 2px; margin-left: -8px;
  border-radius: 2px; background: var(--grad);
}

.nav__actions { display: flex; align-items: center; gap: 8px; margin-left: 8px; }
.nav__links + .nav__actions { margin-left: 0; }

.nav__progress {
  position: absolute; left: 0; bottom: -1px; height: 2px; width: 0;
  background: var(--grad);
  transition: width .1s linear;
}

.icon-btn {
  display: inline-grid; place-items: center;
  width: 38px; height: 38px;
  border: 1px solid var(--border);
  border-radius: 11px;
  background: var(--surface);
  cursor: pointer;
  transition: border-color .2s, background-color .2s, transform .15s;
}
.icon-btn:hover { border-color: var(--border-2); background: var(--surface-2); }
.icon-btn:active { transform: scale(.94); }

.ico--moon { display: none; }
[data-theme="light"] .ico--sun { display: none; }
[data-theme="light"] .ico--moon { display: block; }

.nav__burger { display: none; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 11px 20px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 15px; font-weight: 550;
  cursor: pointer;
  white-space: nowrap;
  transition: transform .18s var(--ease), border-color .2s, background-color .2s, box-shadow .3s;
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn--sm { padding: 7px 14px; font-size: 13.5px; }

.btn--primary {
  position: relative;
  border-color: transparent;
  color: #fff;
  background: var(--grad);
  box-shadow: 0 10px 30px -12px rgba(129,140,248,.7);
}
.btn--primary:hover { box-shadow: 0 16px 38px -12px rgba(129,140,248,.85); }

.btn--ghost { background: var(--surface); color: var(--text-2); }
.btn--ghost:hover { color: var(--text); border-color: var(--border-2); background: var(--surface-2); }

/* ---------- 首屏 ---------- */
.hero {
  padding-top: clamp(56px, 11vh, 128px);
  padding-bottom: clamp(56px, 9vh, 110px);
  text-align: center;
}

.hero__avatar {
  position: relative;
  width: 132px; height: 132px;
  margin: 0 auto 30px;
  display: grid; place-items: center;
}
.hero__avatar img {
  width: 116px; height: 116px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
  background: var(--surface-2);
}
.hero__ring {
  position: absolute; inset: 0;
  border-radius: 50%;
  padding: 2px;
  background: conic-gradient(from 0deg, var(--a1), var(--a2), var(--a3), var(--a1));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  animation: spin 7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.hero__status {
  position: absolute; right: 12px; bottom: 12px;
  width: 16px; height: 16px; border-radius: 50%;
  background: #34d399;
  border: 3px solid var(--bg);
  box-shadow: 0 0 0 0 rgba(52,211,153,.6);
  animation: ping 2.4s ease-out infinite;
}
@keyframes ping {
  70% { box-shadow: 0 0 0 9px rgba(52,211,153,0); }
  100% { box-shadow: 0 0 0 0 rgba(52,211,153,0); }
}

.hero__eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 15px 6px 11px;
  margin-bottom: 22px;
  font-size: 13.5px;
  color: var(--text-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
}
.pulse {
  width: 7px; height: 7px; border-radius: 50%;
  background: #34d399;
  box-shadow: 0 0 8px #34d399;
}

.hero__name {
  font-size: clamp(38px, 8.2vw, 74px);
  line-height: 1.1;
  font-weight: 750;
  letter-spacing: -.02em;
}
.hero__name .grad { padding-right: .06em; }

.hero__tagline {
  max-width: 620px;
  margin: 22px auto 0;
  font-size: clamp(16px, 2.1vw, 19px);
  color: var(--text-2);
}

.hero__cta {
  display: flex; flex-wrap: wrap; justify-content: center; gap: 12px;
  margin-top: 34px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  max-width: 720px;
  margin: 56px auto 0;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  overflow: hidden;
}
.stats__item { padding: 20px 12px; background: var(--bg); }
[data-theme="dark"] .stats__item { background: #0b0d13; }
[data-theme="light"] .stats__item { background: #fff; }
.stats dt { font-size: 12.5px; color: var(--text-3); letter-spacing: .08em; }
.stats dd { margin-top: 4px; font-size: 26px; font-weight: 700; line-height: 1.2; }
.stats dd i { font-style: normal; font-size: 14px; font-weight: 500; color: var(--text-3); margin-left: 2px; }

.hero__social {
  display: flex; justify-content: center; gap: 10px;
  margin-top: 34px;
}
.hero__social a {
  display: grid; place-items: center;
  width: 42px; height: 42px;
  font-size: 17px;
  color: var(--text-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
  transition: color .2s, border-color .2s, transform .18s var(--ease), background-color .2s;
}
.hero__social a:hover {
  color: var(--text);
  border-color: var(--border-2);
  background: var(--surface-2);
  transform: translateY(-3px);
}

/* ---------- 区块通用 ---------- */
.section { padding-block: clamp(48px, 8vh, 92px); }

.sec-head {
  display: flex; align-items: flex-start; gap: 18px;
  margin-bottom: 38px;
}
.sec-head__num {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--text-3);
  padding-top: 6px;
  letter-spacing: .06em;
}
.sec-head__label {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .2em;
  text-transform: uppercase;
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.sec-head__title {
  font-size: clamp(26px, 4.4vw, 36px);
  font-weight: 700;
  letter-spacing: -.015em;
  line-height: 1.25;
}

/* ---------- 卡片 ---------- */
.card {
  position: relative;
  padding: 26px;
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  background: var(--surface);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: var(--shadow);
  transition: border-color .3s, transform .3s var(--ease), background-color .3s;
}
.card::before {
  content: "";
  position: absolute; inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: var(--grad);
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  opacity: 0;
  transition: opacity .35s;
  pointer-events: none;
}
.card:hover { transform: translateY(-3px); }
.card:hover::before { opacity: .5; }

.card__title {
  display: flex; align-items: center; gap: 9px;
  font-size: 15px; font-weight: 650;
  letter-spacing: .02em;
  margin-bottom: 16px;
}
.card__title .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--grad);
}

/* ---------- 关于 ---------- */
.about {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: 20px;
  align-items: start;
}
.about__text p + p { margin-top: 16px; }
.about__text p { color: var(--text-2); }
.about__side { display: grid; gap: 20px; }

.tags { display: flex; flex-wrap: wrap; gap: 8px; }
.tags li {
  padding: 5px 12px;
  font-size: 13.5px;
  color: var(--text-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-2);
  transition: color .2s, border-color .2s, transform .18s var(--ease);
}
.tags li:hover { color: var(--text); border-color: var(--border-2); transform: translateY(-2px); }
.tags--sm li { padding: 3px 10px; font-size: 12.5px; }

.list-check { display: grid; gap: 11px; }
.list-check li {
  position: relative;
  padding-left: 26px;
  font-size: 14.5px;
  color: var(--text-2);
}
.list-check li::before {
  content: "";
  position: absolute; left: 4px; top: .62em;
  width: 9px; height: 9px;
  border-radius: 3px;
  background: var(--grad);
  opacity: .85;
}

/* ---------- 我在玩什么（兴趣） ---------- */
.interests {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(238px, 1fr));
  gap: 20px;
  align-items: stretch;
}

.interest {
  display: flex;
  flex-direction: column;
  padding: 26px 24px;
}

.interest__ico {
  display: grid; place-items: center;
  width: 54px; height: 54px;
  margin-bottom: 20px;
  font-size: 26px;
  line-height: 1;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--grad-soft);
  transition: transform .4s var(--ease), border-color .3s;
}
.interest:hover .interest__ico {
  transform: scale(1.09) rotate(-5deg);
  border-color: var(--border-2);
}

.interest__name {
  font-size: 18px;
  font-weight: 650;
  letter-spacing: -.01em;
  margin-bottom: 9px;
}
.interest__desc {
  flex: 1;
  font-size: 14.5px;
  color: var(--text-2);
}
.interest__meta {
  margin-top: 20px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .07em;
  color: var(--text-3);
}
.interest__meta a {
  color: var(--text-2);
  border-bottom: 1px solid var(--border-2);
  transition: color .2s, border-color .2s;
}
.interest__meta a:hover { color: var(--text); border-bottom-color: var(--a2); }

/* 兴趣卡片里的资料库入口 */
.interest__cta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 4px 10px;
  margin-top: 14px;
  padding: 11px 14px;
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  background: var(--surface-2);
  transition: border-color .22s var(--ease), transform .22s var(--ease);
}
.interest__cta:hover { border-color: var(--border-2); transform: translateY(-1px); }
.interest__cta-t { font-size: 14px; font-weight: 600; }
.interest__cta-s {
  flex: 1;
  min-width: 0;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-3);
}
.interest__cta .ico {
  flex: none;
  width: 16px; height: 16px;
  stroke: var(--a2);
  transition: transform .2s var(--ease);
}
.interest__cta:hover .ico { transform: translateX(3px); }

.interests__note {
  margin-top: 28px;
  text-align: center;
  font-size: 14.5px;
  color: var(--text-3);
}

/* ---------- 时间线 ---------- */
.timeline { position: relative; display: grid; gap: 18px; }
.timeline::before {
  content: "";
  position: absolute; left: 7px; top: 12px; bottom: 12px;
  width: 1px;
  background: linear-gradient(to bottom, transparent, var(--border-2) 12%, var(--border-2) 88%, transparent);
}
.timeline__item { position: relative; padding-left: 34px; }
.timeline__dot {
  position: absolute; left: 0; top: 30px;
  width: 15px; height: 15px; border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--border-2);
}
.timeline__dot::after {
  content: "";
  position: absolute; inset: 3px;
  border-radius: 50%;
  background: var(--grad);
}
.timeline__head {
  display: flex; flex-wrap: wrap; align-items: baseline;
  justify-content: space-between; gap: 10px;
  margin-bottom: 4px;
}
.timeline__head h3 { font-size: 17px; font-weight: 650; }
.timeline__time {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--text-3);
  padding: 2px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
}
.timeline__org { font-size: 13.5px; color: var(--text-3); margin-bottom: 10px; }
.timeline__item p:last-child { color: var(--text-2); font-size: 14.5px; }

/* ---------- 项目 ---------- */
.projects {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(310px, 1fr));
  gap: 20px;
  align-items: start;
}
.project { display: flex; flex-direction: column; }
.project__top {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  margin-bottom: 10px;
}
.project__name {
  display: flex; align-items: center; gap: 9px;
  min-width: 0;
  font-size: 18px; font-weight: 650; letter-spacing: -.01em;
}
.project__icon {
  flex: none;
  width: 26px; height: 26px;
  border-radius: 7px;
  object-fit: cover;
  border: 1px solid var(--border);
}
.project__summary { font-size: 14.5px; color: var(--text); margin-bottom: 10px; }
.project__desc { font-size: 14px; color: var(--text-2); margin-bottom: 18px; }
.project .tags { margin-bottom: 20px; }
.project__links {
  display: flex; flex-wrap: wrap; align-items: center; gap: 16px;
  margin-top: auto;
}

.chip {
  flex: none;
  padding: 3px 10px;
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--text-3);
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-2);
}
.chip--live { color: #34d399; border-color: rgba(52,211,153,.35); background: rgba(52,211,153,.08); }

.link-arrow {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: 14px; font-weight: 550;
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.link-arrow .ico { stroke: var(--a2); transition: transform .2s var(--ease); }
.link-arrow:hover .ico { transform: translate(3px, -3px); }
.link-arrow--muted {
  background: none; -webkit-background-clip: initial; background-clip: initial;
  color: var(--text-3); cursor: default;
}

/* 次要链接（如「下载扩展」） */
.link-arrow--sub {
  background: none; -webkit-background-clip: initial; background-clip: initial;
  color: var(--text-2);
}
.link-arrow--sub .ico { stroke: var(--text-3); }
.link-arrow--sub:hover { color: var(--text); }
.link-arrow--sub:hover .ico { transform: translateY(2px); }

/* 未定项的虚线卡片 */
.project--todo { border-style: dashed; }
.project--todo .project__name { color: var(--text-2); }
.project--todo .tags li { color: var(--text-3); }

/* ---------- 联系 ---------- */
.contact {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: 32px;
  align-items: center;
  padding: 34px;
}
.contact__text h3 { font-size: 22px; font-weight: 700; margin-bottom: 10px; letter-spacing: -.01em; }
.contact__text p { color: var(--text-2); font-size: 14.5px; }

.contact__list { display: grid; gap: 10px; }
.contact__list li {
  display: flex; align-items: center; gap: 14px;
  padding: 13px 15px;
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  background: var(--surface-2);
  transition: border-color .2s, transform .2s var(--ease);
}
.contact__list li:hover { border-color: var(--border-2); transform: translateX(3px); }
.contact__ico {
  display: grid; place-items: center;
  width: 38px; height: 38px; flex: none;
  font-size: 17px;
  border-radius: 11px;
  color: #fff;
  background: var(--grad);
}
.contact__meta { display: grid; min-width: 0; }
.contact__meta b { font-size: 12.5px; font-weight: 500; color: var(--text-3); }
.contact__meta i {
  font-style: normal; font-size: 14.5px;
  color: var(--text);
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
}
.copy-btn {
  margin-left: auto; flex: none;
  padding: 5px 12px;
  font-size: 12.5px;
  color: var(--text-2);
  border: 1px solid var(--border);
  border-radius: 999px;
  background: transparent;
  cursor: pointer;
  transition: color .2s, border-color .2s, background-color .2s;
}
.copy-btn:hover { color: var(--text); border-color: var(--border-2); background: var(--surface); }
.copy-btn.is-done { color: #34d399; border-color: rgba(52,211,153,.4); }
.copy-btn--ghost { cursor: default; opacity: .5; }
.copy-btn--ghost:hover {
  color: var(--text-2); border-color: var(--border); background: transparent;
}

/* ---------- 页脚 ---------- */
.footer {
  margin-top: 40px;
  padding-block: 40px 46px;
  border-top: 1px solid var(--border);
}
.footer__inner { display: grid; gap: 6px; text-align: center; }
.footer__brand { font-weight: 650; letter-spacing: .02em; }
.footer__copy, .footer__beian { font-size: 13px; color: var(--text-3); }
.footer__beian a { transition: color .2s; }
.footer__beian a:hover { color: var(--text-2); }
.footer__beian .sep { margin-inline: 8px; opacity: .5; }

/* ---------- 回到顶部 ---------- */
.to-top {
  position: fixed; right: 22px; bottom: 22px; z-index: 90;
  display: grid; place-items: center;
  width: 44px; height: 44px;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  cursor: pointer;
  opacity: 0; visibility: hidden;
  transform: translateY(10px);
  transition: opacity .3s, transform .3s var(--ease), visibility .3s, border-color .2s;
}
.to-top.is-show { opacity: 1; visibility: visible; transform: translateY(0); }
.to-top:hover { border-color: var(--border-2); }

/* ---------- 入场动画 ---------- */
/* 注意：只在 html.js（JS 可用）时才隐藏元素。
   这样即使 JS 被拦截或加载失败，内容也不会变成一片空白。 */
.js .reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .7s var(--ease) var(--d, 0s), transform .7s var(--ease) var(--d, 0s);
  will-change: opacity, transform;
}
.js .reveal.is-in { opacity: 1; transform: none; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .about, .contact { grid-template-columns: 1fr; }
  .contact { gap: 24px; padding: 26px; }
}

@media (max-width: 720px) {
  :root { --pad: 18px; }

  html { scroll-padding-top: 80px; }

  .nav__burger { display: inline-grid; }

  .nav__links {
    position: absolute; left: var(--pad); right: var(--pad); top: 66px;
    flex-direction: column; align-items: stretch; gap: 2px;
    padding: 10px;
    border: 1px solid var(--border);
    border-radius: var(--r-md);
    background: color-mix(in srgb, var(--bg) 94%, transparent);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    box-shadow: var(--shadow);
    opacity: 0; visibility: hidden;
    transform: translateY(-8px);
    transition: opacity .22s, transform .22s var(--ease), visibility .22s;
  }
  .nav__links.is-open { opacity: 1; visibility: visible; transform: none; }
  .nav__links a { padding: 11px 14px; border-radius: var(--r-sm); }
  .nav__links a.is-active::after { display: none; }
  .nav__links a.is-active { background: var(--surface-2); }

  .nav__actions { margin-left: auto; }
  .nav__actions .btn span { display: none; }
  .nav__actions .btn { padding: 8px 11px; }

  .stats { grid-template-columns: repeat(2, 1fr); }
  .br-mobile { display: none; }
  .to-top { right: 14px; bottom: 14px; }
}

@media (max-width: 400px) {
  .hero__social a { width: 38px; height: 38px; }
  .card { padding: 20px; }
}

/* ---------- 无障碍：尊重系统减弱动效设置 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
  }
  .js .reveal { opacity: 1; transform: none; }
}

/* ---------- 打印 ---------- */
@media print {
  .bg, .nav, .to-top, .hero__cta, .hero__social { display: none !important; }
  body { background: #fff; color: #000; }
  .card { box-shadow: none; border-color: #ddd; }
}