/* =========================================================================
   AI 视频工坊 · 官网设计系统
   base.css —— 变量、排版、布局骨架、通用组件（按钮/卡片/表单/折叠/页脚）
   色板沿用桌面应用 global.css 的 token，保证官网与软件是同一套视觉。
   ========================================================================= */

/* ------------------------------------------------------------ 1. 变量 */
:root {
  /* 品牌色（与桌面应用一致） */
  --accent: #7c5cff;
  --accent-2: #22d3ee;
  --accent-soft: rgba(124, 92, 255, 0.14);
  --accent-line: rgba(124, 92, 255, 0.42);
  --grad: linear-gradient(135deg, #7c5cff 0%, #6d7bff 45%, #22d3ee 100%);
  --grad-text: linear-gradient(104deg, #ffffff 0%, #d6ccff 44%, #8fe8f7 100%);

  /* 深色底 */
  --bg: #07080d;
  --bg-2: #0b0d14;
  --surface: rgba(255, 255, 255, 0.035);
  --surface-2: rgba(255, 255, 255, 0.06);
  --surface-solid: #101320;
  --border: rgba(255, 255, 255, 0.075);
  --border-strong: rgba(255, 255, 255, 0.16);
  --grid-line: rgba(255, 255, 255, 0.028);

  --text: #e9ecf5;
  --text-dim: #9ba4bb;
  --text-mute: #69718a;

  --success: #35d6a4;
  --warning: #fbbf4c;
  --danger: #ff6b81;
  --info: #59a6ff;

  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-pill: 999px;

  --shadow-md: 0 12px 30px -14px rgba(0, 0, 0, 0.6);
  --shadow-lg: 0 24px 60px -20px rgba(0, 0, 0, 0.75);
  --shadow-glow: 0 0 0 1px rgba(124, 92, 255, 0.35), 0 18px 44px -18px rgba(124, 92, 255, 0.6);

  --wrap: 1180px;
  --header-h: 66px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);

  --font: "Segoe UI Variable Display", "Segoe UI", "Microsoft YaHei UI", "Microsoft YaHei",
    "PingFang SC", "Hiragino Sans GB", system-ui, -apple-system, "Helvetica Neue", sans-serif;
  --mono: "Cascadia Code", "JetBrains Mono", "SFMono-Regular", Consolas, "Courier New", monospace;
}

/* ------------------------------------------------------------ 2. 基础重置 */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img,
svg,
video {
  max-width: 100%;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
  border: 0;
  background: none;
}

input,
select,
textarea {
  font: inherit;
  color: inherit;
}

h1,
h2,
h3,
h4 {
  margin: 0;
  line-height: 1.24;
  letter-spacing: -0.015em;
  font-weight: 650;
}

p {
  margin: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

::selection {
  background: rgba(124, 92, 255, 0.34);
  color: #fff;
}

:focus-visible {
  outline: 2px solid rgba(124, 92, 255, 0.85);
  outline-offset: 3px;
  border-radius: 6px;
}

/* 滚动条 */
::-webkit-scrollbar {
  width: 11px;
  height: 11px;
}
::-webkit-scrollbar-track {
  background: #0a0b12;
}
::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.13);
  border: 3px solid #0a0b12;
  border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(124, 92, 255, 0.55);
}

/* ------------------------------------------------------------ 3. 环境光背景 */
.ambience {
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  overflow: hidden;
}

.ambience::before {
  /* 顶部紫青辉光 */
  content: "";
  position: absolute;
  top: -38vh;
  left: 50%;
  width: 150vw;
  height: 110vh;
  transform: translateX(-50%);
  background: radial-gradient(46% 46% at 26% 44%, rgba(124, 92, 255, 0.34), transparent 70%),
    radial-gradient(40% 42% at 76% 36%, rgba(34, 211, 238, 0.22), transparent 72%),
    radial-gradient(60% 50% at 50% 0%, rgba(124, 92, 255, 0.14), transparent 76%);
  filter: blur(6px);
}

.ambience::after {
  /* 细网格 */
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(to right, var(--grid-line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--grid-line) 1px, transparent 1px);
  background-size: 62px 62px;
  mask-image: radial-gradient(78% 58% at 50% 12%, #000 0%, transparent 78%);
  -webkit-mask-image: radial-gradient(78% 58% at 50% 12%, #000 0%, transparent 78%);
}

.page-shell {
  position: relative;
  z-index: 1;
}

/* ------------------------------------------------------------ 4. 布局 */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 26px;
}

.section {
  position: relative;
  padding: clamp(64px, 8.2vw, 118px) 0;
}

.section--tight {
  padding: clamp(44px, 5.5vw, 72px) 0;
}

.section--line {
  border-top: 1px solid var(--border);
}

.section-head {
  max-width: 760px;
  margin-bottom: clamp(30px, 4vw, 52px);
}

.section-head--center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #b9a9ff;
  margin-bottom: 16px;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent));
}

.section-head--center .eyebrow::after {
  content: "";
  width: 22px;
  height: 1px;
  background: linear-gradient(90deg, var(--accent), transparent);
}

h2.section-title {
  font-size: clamp(27px, 3.5vw, 41px);
  letter-spacing: -0.025em;
}

.section-sub {
  margin-top: 16px;
  color: var(--text-dim);
  font-size: clamp(15px, 1.35vw, 17px);
}

.grid {
  display: grid;
  gap: 18px;
}

.cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.cols-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* ------------------------------------------------------------ 5. 顶栏 */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(7, 8, 13, 0.55);
  backdrop-filter: blur(16px) saturate(150%);
  -webkit-backdrop-filter: blur(16px) saturate(150%);
  border-bottom: 1px solid transparent;
  transition: background 0.3s var(--ease), border-color 0.3s var(--ease);
}

.site-header.is-scrolled {
  background: rgba(7, 8, 13, 0.86);
  border-bottom-color: var(--border);
}

.header-inner {
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 20px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  flex-shrink: 0;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 11px;
  display: grid;
  place-items: center;
  background: var(--grad);
  color: #fff;
  box-shadow: 0 8px 22px -10px rgba(124, 92, 255, 0.9);
}

.brand-mark .ico {
  width: 19px;
  height: 19px;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand-text b {
  font-size: 15.5px;
  font-weight: 650;
  letter-spacing: 0.01em;
}

.brand-text i {
  font-style: normal;
  font-size: 10.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-mute);
}

.nav {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-left: 8px;
}

.nav a {
  position: relative;
  padding: 8px 13px;
  border-radius: var(--radius-sm);
  font-size: 14.5px;
  color: var(--text-dim);
  transition: color 0.2s var(--ease), background 0.2s var(--ease);
}

.nav a:hover {
  color: var(--text);
  background: var(--surface);
}

.nav a[aria-current="page"] {
  color: #fff;
}

.nav a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 13px;
  right: 13px;
  bottom: 1px;
  height: 2px;
  border-radius: 2px;
  background: var(--grad);
}

.header-actions {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-toggle {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  place-items: center;
}

.nav-toggle .ico {
  width: 20px;
  height: 20px;
}

/* ------------------------------------------------------------ 6. 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  height: 46px;
  padding: 0 22px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-size: 15px;
  font-weight: 600;
  white-space: nowrap;
  transition: transform 0.18s var(--ease), box-shadow 0.22s var(--ease), background 0.22s var(--ease),
    border-color 0.22s var(--ease), color 0.22s var(--ease);
}

.btn .ico {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
}

.btn:active {
  transform: translateY(1px) scale(0.995);
}

.btn-primary {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 12px 30px -14px rgba(124, 92, 255, 0.95);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 20px 40px -16px rgba(124, 92, 255, 1);
}

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

.btn-ghost:hover {
  background: var(--surface-2);
  border-color: var(--accent-line);
  transform: translateY(-2px);
}

.btn-quiet {
  background: transparent;
  border-color: var(--border);
  color: var(--text-dim);
}

.btn-quiet:hover {
  color: var(--text);
  border-color: var(--border-strong);
}

.btn-sm {
  height: 38px;
  padding: 0 16px;
  font-size: 14px;
}

.btn-lg {
  height: 54px;
  padding: 0 30px;
  font-size: 16.5px;
}

.btn-block {
  width: 100%;
}

.btn[disabled],
.btn.is-loading {
  opacity: 0.62;
  pointer-events: none;
}

/* ------------------------------------------------------------ 7. 徽标 / 药丸 / 文本 */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 32px;
  padding: 0 14px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--accent-line);
  background: var(--accent-soft);
  color: #cfc2ff;
  font-size: 13px;
  font-weight: 550;
}

.badge .ico {
  width: 15px;
  height: 15px;
}

.badge--plain {
  border-color: var(--border);
  background: var(--surface);
  color: var(--text-dim);
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 11px;
  border-radius: var(--radius-pill);
  background: var(--surface-2);
  border: 1px solid var(--border);
  font-size: 12.5px;
  color: var(--text-dim);
}

.pill--ok {
  color: var(--success);
  border-color: rgba(53, 214, 164, 0.28);
  background: rgba(53, 214, 164, 0.1);
}

.pill--run {
  color: #b9a9ff;
  border-color: rgba(124, 92, 255, 0.3);
  background: rgba(124, 92, 255, 0.12);
}

.pill--warn {
  color: var(--warning);
  border-color: rgba(251, 191, 76, 0.28);
  background: rgba(251, 191, 76, 0.1);
}

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

.lead {
  font-size: clamp(16px, 1.6vw, 19px);
  color: var(--text-dim);
  line-height: 1.78;
}

.muted {
  color: var(--text-mute);
}

.dim {
  color: var(--text-dim);
}

.small {
  font-size: 13.5px;
}

.mono {
  font-family: var(--mono);
  font-size: 13px;
}

.ico {
  display: inline-block;
  width: 24px;
  height: 24px;
  vertical-align: -0.16em;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.ico--fill {
  fill: currentColor;
  stroke: none;
}

/* ------------------------------------------------------------ 8. 卡片 */
.card {
  position: relative;
  padding: 26px 24px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.055), rgba(255, 255, 255, 0.018));
  transition: transform 0.28s var(--ease), border-color 0.28s var(--ease), box-shadow 0.28s var(--ease);
}

.card--hover:hover {
  transform: translateY(-4px);
  border-color: var(--accent-line);
  box-shadow: var(--shadow-glow);
}

.card--flat {
  background: var(--surface);
}

.card--pad-lg {
  padding: 32px 30px;
}

.card-icon {
  width: 46px;
  height: 46px;
  border-radius: 13px;
  display: grid;
  place-items: center;
  margin-bottom: 18px;
  color: #fff;
  background: linear-gradient(150deg, rgba(124, 92, 255, 0.9), rgba(34, 211, 238, 0.62));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.28);
}

.card-icon .ico {
  width: 22px;
  height: 22px;
}

.card h3 {
  font-size: 17.5px;
  margin-bottom: 9px;
}

.card p {
  color: var(--text-dim);
  font-size: 14.6px;
  line-height: 1.72;
}

.card-list {
  margin-top: 16px;
  display: grid;
  gap: 9px;
}

.card-list li {
  position: relative;
  padding-left: 24px;
  font-size: 14.4px;
  color: var(--text-dim);
}

.card-list li::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 9px;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--grad);
}

.check-list {
  display: grid;
  gap: 11px;
}

.check-list li {
  display: flex;
  gap: 11px;
  align-items: flex-start;
  font-size: 14.8px;
  color: var(--text-dim);
}

.check-list .ico {
  width: 19px;
  height: 19px;
  margin-top: 3px;
  color: var(--success);
  flex-shrink: 0;
}

.plain-list {
  display: grid;
  gap: 10px;
  color: var(--text-dim);
  font-size: 14.6px;
}

/* 统计条 */
.stat-row {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--border);
}

.stat {
  padding: 24px 22px;
  background: rgba(11, 13, 20, 0.72);
}

.stat b {
  display: block;
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 680;
  letter-spacing: -0.02em;
  background: var(--grad-text);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.stat span {
  display: block;
  margin-top: 6px;
  font-size: 13.4px;
  color: var(--text-dim);
}

/* ------------------------------------------------------------ 9. 表单 */
.field {
  display: grid;
  gap: 7px;
}

.field label {
  font-size: 13.6px;
  color: var(--text-dim);
}

.input {
  width: 100%;
  height: 48px;
  padding: 0 16px;
  border-radius: var(--radius);
  border: 1px solid var(--border-strong);
  background: rgba(9, 11, 18, 0.72);
  color: var(--text);
  transition: border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.input::placeholder {
  color: var(--text-mute);
}

.input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(124, 92, 255, 0.16);
}

.input.invalid {
  border-color: var(--danger);
  box-shadow: 0 0 0 4px rgba(255, 107, 129, 0.14);
}

.subscribe {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.subscribe .input {
  flex: 1 1 260px;
  min-width: 0;
}

.form-hint {
  margin-top: 12px;
  font-size: 13.4px;
  color: var(--text-mute);
  line-height: 1.7;
}

.sub-fallback {
  margin-top: 14px;
  padding: 14px 16px;
  border-radius: var(--radius);
  border: 1px dashed var(--border-strong);
  background: var(--surface);
  font-size: 13.8px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

/* 轻提示 */
.site-toast {
  position: fixed;
  left: 50%;
  bottom: 32px;
  transform: translate(-50%, 18px);
  z-index: 200;
  max-width: min(90vw, 460px);
  padding: 13px 20px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--accent-line);
  background: rgba(16, 19, 32, 0.95);
  backdrop-filter: blur(10px);
  color: var(--text);
  font-size: 14px;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}

.site-toast.show {
  opacity: 1;
  transform: translate(-50%, 0);
}

/* ------------------------------------------------------------ 10. 折叠面板 */
.faq {
  display: grid;
  gap: 12px;
}

.faq-item {
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  background: var(--surface);
  overflow: hidden;
  transition: border-color 0.25s var(--ease), background 0.25s var(--ease);
}

.faq-item.open {
  border-color: var(--accent-line);
  background: linear-gradient(180deg, rgba(124, 92, 255, 0.09), rgba(255, 255, 255, 0.02));
}

.faq-q {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 20px 22px;
  text-align: left;
  font-size: 16px;
  font-weight: 580;
}

.faq-q .ico {
  width: 20px;
  height: 20px;
  margin-left: auto;
  flex-shrink: 0;
  color: var(--text-mute);
  transition: transform 0.3s var(--ease), color 0.25s var(--ease);
}

.faq-item.open .faq-q .ico {
  transform: rotate(180deg);
  color: var(--accent-2);
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.36s var(--ease);
}

.faq-a > div {
  padding: 0 22px 21px;
  color: var(--text-dim);
  font-size: 14.8px;
  line-height: 1.78;
}

.faq-a code {
  font-family: var(--mono);
  font-size: 13px;
  padding: 2px 6px;
  border-radius: 6px;
  background: rgba(255, 255, 255, 0.07);
  color: #cbbfff;
}

/* ------------------------------------------------------------ 11. 跑马灯 */
.marquee {
  position: relative;
  overflow: hidden;
  padding: 6px 0;
  mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
}

.marquee-track {
  display: flex;
  align-items: center;
  gap: 14px;
  width: max-content;
}

.marquee-track.is-ready {
  animation: marquee 38s linear infinite;
}

.marquee:hover .marquee-track {
  animation-play-state: paused;
}

.marquee-item {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  height: 42px;
  padding: 0 20px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-dim);
  font-size: 14px;
  white-space: nowrap;
}

.marquee-item .ico {
  width: 17px;
  height: 17px;
  color: #b9a9ff;
}

@keyframes marquee {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(-50%);
  }
}

/* ------------------------------------------------------------ 12. 页脚 */
.site-footer {
  position: relative;
  margin-top: 40px;
  border-top: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(11, 13, 20, 0.5), rgba(7, 8, 13, 0.95));
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr repeat(3, 1fr);
  gap: 34px;
  padding: 56px 26px 40px;
}

.footer-brand p {
  margin-top: 16px;
  max-width: 320px;
  color: var(--text-mute);
  font-size: 13.8px;
  line-height: 1.75;
}

.footer-col h4 {
  font-size: 13px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 16px;
  font-weight: 600;
}

.footer-col a,
.footer-col span {
  display: block;
  padding: 6px 0;
  font-size: 14.2px;
  color: var(--text-dim);
  transition: color 0.2s var(--ease), transform 0.2s var(--ease);
}

.footer-col a:hover {
  color: #fff;
  transform: translateX(3px);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  flex-wrap: wrap;
  padding: 20px 26px 34px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-mute);
}

.footer-bottom a:hover {
  color: var(--text);
}

.footer-legal {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ------------------------------------------------------------ 13. 滚动显现 */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
  transition-delay: var(--d, 0ms);
}

.reveal.in {
  opacity: 1;
  transform: none;
}

/* ------------------------------------------------------------ 14. 工具类 */
.center {
  text-align: center;
}

.stack {
  display: grid;
  gap: 16px;
}

.row {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.row--center {
  justify-content: center;
}

.mt-0 {
  margin-top: 0;
}
.mt-8 {
  margin-top: 8px;
}
.mt-16 {
  margin-top: 16px;
}
.mt-24 {
  margin-top: 24px;
}
.mt-32 {
  margin-top: 32px;
}
.mt-48 {
  margin-top: 48px;
}
.mb-0 {
  margin-bottom: 0;
}
.mb-16 {
  margin-bottom: 16px;
}
.mb-24 {
  margin-bottom: 24px;
}
.hidden {
  display: none !important;
}
[hidden] {
  display: none !important;
}

.divider {
  height: 1px;
  background: var(--border);
  border: 0;
  margin: 32px 0;
}

/* ------------------------------------------------------------ 15. 响应式 */
@media (max-width: 1024px) {
  .cols-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .stat-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 28px;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: grid;
  }
  .nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    margin: 0;
    padding: 14px 20px 22px;
    background: rgba(9, 11, 18, 0.97);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.26s var(--ease), opacity 0.26s var(--ease), visibility 0.26s;
  }
  .nav a {
    padding: 13px 14px;
    font-size: 16px;
    border-radius: var(--radius);
  }
  .nav a[aria-current="page"]::after {
    display: none;
  }
  .nav a[aria-current="page"] {
    background: var(--accent-soft);
    color: #d9cfff;
  }
  html.nav-open .nav {
    transform: none;
    opacity: 1;
    visibility: visible;
  }
  .cols-3,
  .cols-2 {
    grid-template-columns: 1fr;
  }
  .hide-sm {
    display: none !important;
  }
}

@media (max-width: 620px) {
  body {
    font-size: 15.4px;
  }
  .wrap {
    padding: 0 18px;
  }
  /* 顶栏：隐藏品牌英文副标题 + 按钮用短文案，避免 390px 下顶栏被撑破 */
  .brand-text i {
    display: none;
  }
  .hide-xs {
    display: none !important;
  }
  .show-xs {
    display: inline;
  }
  .header-actions {
    gap: 8px;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    padding: 42px 18px 28px;
  }
  .footer-bottom {
    padding: 18px 18px 30px;
  }
  .btn {
    height: 44px;
    padding: 0 18px;
    font-size: 14.5px;
  }
  .btn-lg {
    height: 50px;
    width: 100%;
  }
  .stat-row {
    grid-template-columns: 1fr;
  }
  .card {
    padding: 22px 19px;
  }
  /* 两列内容（按钮 + 文案）在窄屏一律竖排，避免内联 flex-basis 撑破容器 */
  .cta-band .row {
    gap: 18px !important;
    align-items: stretch !important;
  }
  .cta-band .row > div {
    flex: 1 1 100% !important;
    min-width: 0;
  }
  .cta-band .btn {
    width: 100%;
  }
  .cta-band .row .row {
    width: 100%;
  }
}

/* ------------------------------------------------------------ 16. 动效偏好 */
@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;
  }
}