/* =========================================================
   202540.xyz — 站点样式
   纯手写 CSS，无框架、无外部字体、无构建步骤。
   结构：1) 变量  2) 基础  3) 布局  4) 组件  5) 响应式
   ========================================================= */

/* ---------- 1) 设计变量 ---------- */
:root {
  --wrap: 1080px;
  --gutter: clamp(1.15rem, 4vw, 2.5rem);
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --ring: 2px solid var(--accent-1);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --dur: 0.45s;

  /* 深色（默认） */
  --bg: #07080c;
  --bg-soft: #0b0d15;
  --surface: rgba(255, 255, 255, 0.035);
  --surface-2: rgba(255, 255, 255, 0.065);
  --border: rgba(255, 255, 255, 0.09);
  --border-strong: rgba(255, 255, 255, 0.18);
  --text: #e9ecf5;
  --text-dim: #b8c0d4;
  --muted: #8f98b0;
  --accent-1: #8b6cff;
  --accent-2: #2ad4ee;
  --accent-3: #f472b6;
  --shadow: 0 18px 50px -22px rgba(0, 0, 0, 0.85);
  --glow: 0 0 0 1px rgba(255, 255, 255, 0.04), 0 22px 60px -30px rgba(139, 108, 255, 0.75);
  --aurora-a: rgba(124, 92, 255, 0.5);
  --aurora-b: rgba(34, 211, 238, 0.32);
  --aurora-c: rgba(244, 114, 182, 0.24);
}

[data-theme="light"] {
  --bg: #f6f7fc;
  --bg-soft: #ffffff;
  --surface: rgba(16, 20, 38, 0.025);
  --surface-2: rgba(16, 20, 38, 0.05);
  --border: rgba(16, 20, 38, 0.1);
  --border-strong: rgba(16, 20, 38, 0.2);
  --text: #11141f;
  --text-dim: #3b4356;
  --muted: #616b82;
  --accent-1: #5b3df0;
  --accent-2: #0a92ad;
  --accent-3: #d6408f;
  --shadow: 0 18px 44px -26px rgba(23, 27, 51, 0.35);
  --glow: 0 0 0 1px rgba(16, 20, 38, 0.04), 0 20px 44px -28px rgba(91, 61, 240, 0.45);
  --aurora-a: rgba(124, 92, 255, 0.3);
  --aurora-b: rgba(34, 211, 238, 0.24);
  --aurora-c: rgba(244, 114, 182, 0.18);
}

/* ---------- 2) 基础 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Noto Sans SC", sans-serif;
  font-size: clamp(15px, 0.55vw + 13.6px, 17px);
  line-height: 1.7;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  transition: background-color 0.3s var(--ease), color 0.3s var(--ease);
}

h1, h2, h3 {
  margin: 0;
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 700;
  text-wrap: balance;
}

p { margin: 0; }
ul, dl, dd { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }

svg {
  width: 1em;
  height: 1em;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

:focus-visible {
  outline: var(--ring);
  outline-offset: 3px;
  border-radius: 6px;
}

::selection {
  background: color-mix(in srgb, var(--accent-1) 45%, transparent);
  color: #fff;
}

.skip-link {
  position: fixed;
  top: -100px;
  left: 1rem;
  z-index: 100;
  padding: 0.7rem 1.1rem;
  border-radius: var(--radius-sm);
  background: var(--accent-1);
  color: #fff;
  font-weight: 600;
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 1rem; }

/* ---------- 3) 布局 ---------- */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

main { display: block; }

.section { padding-block: clamp(3.5rem, 9vw, 6.5rem) 0; }

/* 背景光晕 */
.aurora {
  position: fixed;
  inset: 0;
  z-index: -1;
  overflow: hidden;
  pointer-events: none;
  background:
    radial-gradient(120% 80% at 50% -10%, var(--bg-soft), transparent 60%);
}

.aurora__blob {
  position: absolute;
  display: block;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.9;
  animation: float 26s var(--ease) infinite alternate;
}
.aurora__blob--1 {
  width: 46vw; height: 46vw; min-width: 320px; min-height: 320px;
  top: -14vw; left: -8vw;
  background: var(--aurora-a);
}
.aurora__blob--2 {
  width: 38vw; height: 38vw; min-width: 260px; min-height: 260px;
  top: 6vw; right: -10vw;
  background: var(--aurora-b);
  animation-delay: -8s;
}
.aurora__blob--3 {
  width: 34vw; height: 34vw; min-width: 240px; min-height: 240px;
  top: 42vh; left: 30vw;
  background: var(--aurora-c);
  animation-delay: -15s;
}

@keyframes float {
  from { transform: translate3d(0, 0, 0) scale(1); }
  to   { transform: translate3d(3vw, 5vh, 0) scale(1.14); }
}

/* ---------- 4) 组件 ---------- */
/* 顶栏 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  transition: background-color 0.3s var(--ease), border-color 0.3s var(--ease),
    backdrop-filter 0.3s var(--ease);
  border-bottom: 1px solid transparent;
}
.site-header.is-scrolled {
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom-color: var(--border);
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 4.25rem;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.brand__mark {
  display: grid;
  place-items: center;
  width: 2rem;
  height: 2rem;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: #fff;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  box-shadow: 0 8px 22px -10px color-mix(in srgb, var(--accent-1) 90%, transparent);
}
.brand__tld { color: var(--muted); font-weight: 600; }

.nav {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav__link {
  position: relative;
  padding: 0.5rem 0.8rem;
  border-radius: 999px;
  color: var(--text-dim);
  font-size: 0.95rem;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease);
}
.nav__link:hover {
  color: var(--text);
  background: var(--surface-2);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 2.4rem;
  height: 2.4rem;
  margin-left: 0.25rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-dim);
  cursor: pointer;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease),
    background-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.theme-toggle:hover {
  color: var(--text);
  border-color: var(--border-strong);
  transform: translateY(-1px);
}
.theme-toggle__icon {
  width: 1.1rem;
  height: 1.1rem;
  stroke-width: 1.7;
  grid-area: 1 / 1;
  transition: opacity 0.25s var(--ease), transform 0.35s var(--ease);
}
[data-theme="dark"] .theme-toggle__icon--sun { opacity: 1; transform: rotate(0); }
[data-theme="dark"] .theme-toggle__icon--moon { opacity: 0; transform: rotate(-70deg) scale(0.6); }
[data-theme="light"] .theme-toggle__icon--sun { opacity: 0; transform: rotate(70deg) scale(0.6); }
[data-theme="light"] .theme-toggle__icon--moon { opacity: 1; transform: rotate(0); }

.nav-toggle {
  display: none;
  position: relative;
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  cursor: pointer;
}
.nav-toggle__bar {
  position: absolute;
  left: 50%;
  width: 1rem;
  height: 2px;
  border-radius: 2px;
  background: var(--text);
  transform: translateX(-50%);
  transition: transform 0.25s var(--ease), opacity 0.2s var(--ease);
}
.nav-toggle__bar:nth-child(1) { top: 0.95rem; }
.nav-toggle__bar:nth-child(2) { top: 1.35rem; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) { transform: translateX(-50%) translateY(0.2rem) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) { transform: translateX(-50%) translateY(-0.2rem) rotate(-45deg); }

/* 首屏 */
.hero {
  padding-block: clamp(3rem, 10vw, 7rem) clamp(2rem, 5vw, 3rem);
  max-width: 62rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-size: 0.82rem;
  letter-spacing: 0.02em;
}
.pill__dot {
  width: 0.45rem;
  height: 0.45rem;
  border-radius: 50%;
  background: #34d399;
  box-shadow: 0 0 0 0 rgba(52, 211, 153, 0.6);
  animation: pulse 2.6s ease-out infinite;
}
.pill__sep { opacity: 0.5; }

@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0.55); }
  70%  { box-shadow: 0 0 0 0.6rem rgba(52, 211, 153, 0); }
  100% { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0); }
}

.hero__title {
  margin-block: clamp(1.1rem, 3vw, 1.6rem) 0;
  font-size: clamp(2.35rem, 7.4vw, 4.6rem);
  font-weight: 800;
  letter-spacing: -0.035em;
}

.grad {
  background: linear-gradient(100deg, var(--accent-1) 0%, var(--accent-2) 55%, var(--accent-3) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
}

.hero__lead {
  margin-top: clamp(1rem, 2.5vw, 1.4rem);
  max-width: 34rem;
  color: var(--text-dim);
  font-size: clamp(1rem, 0.6vw + 0.9rem, 1.2rem);
  line-height: 1.75;
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: clamp(1.6rem, 4vw, 2.2rem);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.78rem 1.35rem;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 0.96rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.22s var(--ease), box-shadow 0.28s var(--ease),
    background-color 0.22s var(--ease), border-color 0.22s var(--ease), color 0.22s var(--ease);
}
.btn svg { width: 1.05em; height: 1.05em; transition: transform 0.25s var(--ease); }
.btn:hover { transform: translateY(-2px); }
.btn:hover svg { transform: translateX(3px); }

.btn--primary {
  background: linear-gradient(135deg, var(--accent-1), var(--accent-2));
  color: #fff;
  box-shadow: var(--glow);
}
.btn--primary:hover { box-shadow: 0 26px 55px -22px color-mix(in srgb, var(--accent-1) 85%, transparent); }

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

.facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(9.5rem, 1fr));
  gap: 1px;
  margin-top: clamp(2.4rem, 6vw, 3.6rem);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--border);
  overflow: hidden;
}
.facts__item {
  padding: 1rem 1.2rem;
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  backdrop-filter: blur(6px);
}
.facts dt {
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.facts dd {
  margin-top: 0.25rem;
  font-weight: 600;
}

/* 区块标题 */
.section__head { margin-bottom: clamp(1.8rem, 4vw, 2.6rem); }

.eyebrow {
  margin-bottom: 0.5rem;
  color: var(--accent-2);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}
[data-theme="light"] .eyebrow { color: var(--accent-1); }

.section__title { font-size: clamp(1.6rem, 3.4vw, 2.3rem); }

.section__sub {
  margin-top: 0.7rem;
  max-width: 38rem;
  color: var(--muted);
}

/* 关于 */
.about {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: start;
}
.about__text p + p { margin-top: 1rem; }
.about__text { color: var(--text-dim); }

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.chip {
  padding: 0.4rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-dim);
  font-size: 0.85rem;
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease), color 0.22s var(--ease);
}
.chip:hover {
  transform: translateY(-2px);
  border-color: var(--border-strong);
  color: var(--text);
}

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(8rem, 1fr));
  gap: clamp(1rem, 3vw, 1.6rem);
  margin-top: clamp(2.2rem, 5vw, 3.2rem);
  padding-top: clamp(1.6rem, 4vw, 2.2rem);
  border-top: 1px solid var(--border);
}
.stat__num {
  display: block;
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(120deg, var(--accent-1), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  -webkit-text-fill-color: transparent;
  font-variant-numeric: tabular-nums;
}
.stat__label {
  display: block;
  margin-top: 0.15rem;
  color: var(--muted);
  font-size: 0.88rem;
}

/* 卡片 */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr));
  gap: clamp(0.9rem, 2.4vw, 1.4rem);
}

.card {
  position: relative;
  padding: clamp(1.3rem, 3vw, 1.8rem);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--surface);
  overflow: hidden;
  transition: transform 0.3s var(--ease), border-color 0.3s var(--ease),
    background-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.card::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(60% 55% at 20% 0%, color-mix(in srgb, var(--accent-1) 22%, transparent), transparent 70%);
  opacity: 0;
  transition: opacity 0.35s var(--ease);
  pointer-events: none;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  background: var(--surface-2);
  box-shadow: var(--shadow);
}
.card:hover::after { opacity: 1; }

.card__icon {
  display: grid;
  place-items: center;
  width: 2.6rem;
  height: 2.6rem;
  margin-bottom: 1rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: linear-gradient(140deg, color-mix(in srgb, var(--accent-1) 26%, transparent), transparent);
  color: var(--accent-2);
}
.card__icon svg { width: 1.25rem; height: 1.25rem; }
[data-theme="light"] .card__icon { color: var(--accent-1); }

.card__title { font-size: 1.12rem; }
.card__desc {
  margin-top: 0.5rem;
  color: var(--muted);
  font-size: 0.94rem;
  line-height: 1.65;
}
.card__meta {
  display: inline-block;
  margin-top: 1.1rem;
  color: var(--accent-2);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
}
[data-theme="light"] .card__meta { color: var(--accent-1); }

/* 联系 */
.contact {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr);
  gap: clamp(1.6rem, 4vw, 3rem);
  align-items: center;
  margin-bottom: clamp(3rem, 8vw, 5rem);
  padding: clamp(1.6rem, 4vw, 2.8rem);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background:
    radial-gradient(90% 120% at 100% 0%, color-mix(in srgb, var(--accent-1) 14%, transparent), transparent 60%),
    var(--surface);
}

.contact__actions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.copy {
  display: grid;
  gap: 0.15rem;
  width: 100%;
  padding: 1rem 1.2rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--bg) 55%, transparent);
  color: inherit;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: border-color 0.22s var(--ease), transform 0.22s var(--ease), background-color 0.22s var(--ease);
}
.copy:hover {
  transform: translateY(-2px);
  border-color: var(--border-strong);
  background: var(--surface-2);
}
.copy__label {
  color: var(--muted);
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.copy__value {
  font-size: 1.02rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.copy__hint {
  color: var(--muted);
  font-size: 0.78rem;
}
.copy.is-copied { border-color: color-mix(in srgb, var(--accent-2) 60%, transparent); }

.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
}
.link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 1rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-dim);
  font-size: 0.9rem;
  transition: color 0.22s var(--ease), border-color 0.22s var(--ease), transform 0.22s var(--ease);
}
.link svg { width: 0.95em; height: 0.95em; }
.link:hover {
  color: var(--text);
  border-color: var(--border-strong);
  transform: translateY(-2px);
}

/* 页脚 */
.site-footer {
  padding-block: 2rem 2.6rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.88rem;
}
.site-footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  justify-content: space-between;
}

/* 滚动入场动画 */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  transition-delay: var(--reveal-delay, 0ms);
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
}

/* ---------- 5) 响应式 ---------- */
@media (max-width: 860px) {
  .about,
  .contact {
    grid-template-columns: minmax(0, 1fr);
  }
  .contact { align-items: start; }
}

@media (max-width: 640px) {
  .br-wide { display: none; }

  .nav-toggle { display: block; }

  .nav {
    position: absolute;
    top: calc(100% + 0.6rem);
    right: var(--gutter);
    left: var(--gutter);
    flex-direction: column;
    align-items: stretch;
    gap: 0.25rem;
    padding: 0.6rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: color-mix(in srgb, var(--bg) 92%, transparent);
    backdrop-filter: saturate(160%) blur(16px);
    -webkit-backdrop-filter: saturate(160%) blur(16px);
    box-shadow: var(--shadow);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0.25s;
  }
  .nav.is-open {
    opacity: 1;
    visibility: visible;
    transform: none;
  }
  .nav__link { padding: 0.7rem 0.9rem; border-radius: var(--radius-sm); }
  .theme-toggle { margin: 0.25rem 0 0; justify-self: start; }

  .facts { grid-template-columns: repeat(auto-fit, minmax(7.5rem, 1fr)); }
}

/* 尊重系统的“减少动态效果”设置 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .reveal { opacity: 1; transform: none; }
}

/* 打印 */
@media print {
  .aurora, .site-header, .site-footer, .hero__cta { display: none; }
  body { background: #fff; color: #000; }
}