/* ============================================================
   28圈注册 — 共享站点样式 /assets/site.css
   深墨蓝底 · 暖纸色内容层 · 霓虹青链接 · 珊瑚橙行动 · 暖金更新标记
   ============================================================ */

/* ---------- 1. 设计变量 ---------- */
:root {
  --c28-ink: #0B1220;
  --c28-ink-2: #111C33;
  --c28-ink-3: #16233F;
  --c28-paper: #F7F1E5;
  --c28-paper-2: #E9DFC9;
  --c28-cyan: #39E0D0;
  --c28-coral: #FF6B4A;
  --c28-gold: #E6B85C;
  --c28-slate: #6B7280;
  --c28-green: #2DBE7A;
  --c28-red: #D64545;

  --c28-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  --c28-mono: "JetBrains Mono", "SFMono-Regular", "Cascadia Mono", "Noto Sans Mono", ui-monospace, Menlo, Consolas, monospace;

  --c28-hair: rgba(247, 241, 229, 0.13);
  --c28-hair-strong: rgba(247, 241, 229, 0.26);
  --c28-text-dim: rgba(247, 241, 229, 0.68);
  --c28-ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --c28-radius: 18px;
  --c28-radius-sm: 12px;
}

/* ---------- 2. reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body {
  margin: 0;
  padding-top: 88px;
  background-color: var(--c28-ink);
  background-image:
    radial-gradient(90% 55% at 6% -8%, rgba(57, 224, 208, 0.14), transparent 62%),
    radial-gradient(76% 48% at 102% 2%, rgba(230, 184, 92, 0.10), transparent 60%);
  background-repeat: no-repeat;
  color: var(--c28-paper);
  font-family: var(--c28-sans);
  font-size: 17px;
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3, h4 {
  margin: 0 0 0.6em;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.26;
}

p { margin: 0 0 1em; }

a { color: var(--c28-cyan); text-underline-offset: 3px; }

button { font: inherit; color: inherit; }

#main-content { scroll-margin-top: 92px; }

/* ---------- 3. 焦点与无障碍 ---------- */
:focus-visible {
  outline: 2px solid var(--c28-cyan);
  outline-offset: 3px;
  border-radius: 6px;
}

.c28-skip {
  position: fixed;
  left: 50%;
  top: 8px;
  z-index: 999;
  transform: translate(-50%, -180%);
  padding: 11px 22px;
  border-radius: 999px;
  background: var(--c28-cyan);
  color: #04231F;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  box-shadow: 0 18px 38px -18px rgba(57, 224, 208, 0.95);
  transition: transform 0.2s var(--c28-ease);
}
.c28-skip:focus {
  transform: translate(-50%, 0);
}

/* ---------- 4. 布局壳 ---------- */
.c28-shell {
  width: min(1280px, calc(100% - 2.5rem));
  margin-inline: auto;
}

.c28-section { padding-block: clamp(44px, 6vw, 88px); }
.c28-section--tight { padding-block: clamp(26px, 3.6vw, 48px); }

.c28-grid {
  display: grid;
  gap: clamp(14px, 1.8vw, 22px);
}
.c28-grid--2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.c28-grid--3 { grid-template-columns: repeat(auto-fit, minmax(235px, 1fr)); }
.c28-grid--4 { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }

/* ---------- 5. 排版元件 ---------- */
.c28-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 14px;
  font-family: var(--c28-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--c28-cyan);
}
.c28-eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--c28-cyan);
  opacity: 0.75;
}

.c28-heading {
  font-size: clamp(1.6rem, 3vw, 2.4rem);
  margin: 0 0 0.45em;
}

.c28-lede {
  max-width: 62ch;
  margin: 0 0 1.5em;
  font-size: clamp(1rem, 1.25vw, 1.125rem);
  line-height: 1.8;
  color: var(--c28-text-dim);
}

.c28-prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.8;
}
.c28-prose h2 {
  margin-top: 1.8em;
  font-size: clamp(1.35rem, 2.2vw, 1.75rem);
}
.c28-prose h3 {
  margin-top: 1.5em;
  font-size: 1.18rem;
}
.c28-prose p,
.c28-prose ul,
.c28-prose ol { margin: 0 0 1.1em; }
.c28-prose ul { padding-left: 0; list-style: none; }
.c28-prose ul li {
  position: relative;
  padding-left: 1.45em;
}
.c28-prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--c28-cyan);
}
.c28-prose ol { padding-left: 1.4em; }
.c28-prose ol li { margin-bottom: 0.4em; }
.c28-prose blockquote {
  margin: 1.6em 0;
  padding: 14px 20px;
  border-left: 3px solid var(--c28-gold);
  border-radius: 0 var(--c28-radius-sm) var(--c28-radius-sm) 0;
  background: rgba(230, 184, 92, 0.08);
  color: rgba(247, 241, 229, 0.86);
}
.c28-prose code,
.c28-prose kbd {
  font-family: var(--c28-mono);
  font-size: 0.9em;
  padding: 2px 6px;
  border-radius: 6px;
  background: rgba(247, 241, 229, 0.08);
  letter-spacing: 0.02em;
}

/* ---------- 6. 卡片 / 按钮 / 标签 ---------- */
.c28-card {
  position: relative;
  padding: clamp(18px, 2vw, 26px);
  border: 1px solid var(--c28-hair);
  border-radius: var(--c28-radius);
  background: rgba(17, 28, 51, 0.72);
  -webkit-backdrop-filter: blur(10px) saturate(130%);
  backdrop-filter: blur(10px) saturate(130%);
  transition: transform 0.2s var(--c28-ease), border-color 0.2s var(--c28-ease), box-shadow 0.2s var(--c28-ease);
}
.c28-card:hover {
  transform: translateY(-3px);
  border-color: rgba(57, 224, 208, 0.4);
  box-shadow: 0 26px 54px -34px rgba(57, 224, 208, 0.55);
}
.c28-card--paper {
  background: var(--c28-paper);
  color: var(--c28-ink);
  border-color: rgba(11, 18, 32, 0.14);
}
.c28-card--paper:hover {
  border-color: rgba(11, 18, 32, 0.32);
  box-shadow: 0 26px 54px -36px rgba(0, 0, 0, 0.8);
}
.c28-card__title {
  margin: 0 0 0.4em;
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.c28-card__meta {
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--c28-gold);
}
.c28-card--paper .c28-card__meta { color: #5A5F6B; }

.c28-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 700;
  line-height: 1.2;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.18s var(--c28-ease), background 0.18s var(--c28-ease), border-color 0.18s var(--c28-ease), color 0.18s var(--c28-ease);
}
.c28-btn--solid {
  background: var(--c28-coral);
  color: #2A0D06;
  box-shadow: 0 14px 30px -16px rgba(255, 107, 74, 0.95);
}
.c28-btn--solid:hover { transform: translateY(-2px); background: #FF8368; }
.c28-btn--line {
  border-color: rgba(57, 224, 208, 0.5);
  background: rgba(57, 224, 208, 0.08);
  color: var(--c28-cyan);
}
.c28-btn--line:hover { transform: translateY(-2px); background: rgba(57, 224, 208, 0.16); }
.c28-btn--ghost {
  border-color: var(--c28-hair-strong);
  background: transparent;
  color: var(--c28-paper);
}
.c28-btn--ghost:hover { transform: translateY(-2px); border-color: rgba(247, 241, 229, 0.48); }

.c28-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid rgba(57, 224, 208, 0.42);
  border-radius: 999px;
  background: rgba(57, 224, 208, 0.08);
  color: var(--c28-cyan);
  font-family: var(--c28-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  white-space: nowrap;
}
.c28-tag--gold {
  border-color: rgba(230, 184, 92, 0.45);
  background: rgba(230, 184, 92, 0.09);
  color: var(--c28-gold);
}
.c28-tag--coral {
  border-color: rgba(255, 107, 74, 0.45);
  background: rgba(255, 107, 74, 0.1);
  color: #FF8A6E;
}

/* ---------- 7. 面包屑 ---------- */
.c28-breadcrumb { margin-bottom: clamp(16px, 2vw, 26px); }
.c28-breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
}
.c28-breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--c28-slate);
}
.c28-breadcrumb li + li::before {
  content: "/";
  color: rgba(247, 241, 229, 0.26);
}
.c28-breadcrumb a {
  color: var(--c28-text-dim);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--c28-ease), border-color 0.18s var(--c28-ease);
}
.c28-breadcrumb a:hover {
  color: var(--c28-cyan);
  border-bottom-color: var(--c28-cyan);
}
.c28-breadcrumb [aria-current="page"] { color: var(--c28-paper); }

/* ---------- 8. 图片容器（供页面阶段放置配图） ---------- */
.c28-media {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--c28-hair);
  border-radius: var(--c28-radius-sm);
  background-color: var(--c28-ink-2);
  background-image:
    linear-gradient(rgba(247, 241, 229, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(247, 241, 229, 0.055) 1px, transparent 1px),
    radial-gradient(120% 95% at 10% 6%, rgba(57, 224, 208, 0.22), transparent 60%),
    radial-gradient(110% 90% at 94% 98%, rgba(230, 184, 92, 0.18), transparent 62%);
  background-size: 32px 32px, 32px 32px, 100% 100%, 100% 100%;
}
.c28-media__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.c28-media--wide { aspect-ratio: 21 / 9; }
.c28-media--square { aspect-ratio: 1 / 1; }
.c28-media--tall { aspect-ratio: 3 / 4; }
.c28-media__caption {
  margin: 10px 0 0;
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--c28-slate);
}

/* ---------- 9. 滚动显现 ---------- */
.is-reveal-ready {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.55s var(--c28-ease), transform 0.55s var(--c28-ease);
}
.is-revealed {
  opacity: 1;
  transform: none;
}

/* ---------- 10. 头部：悬浮胶囊导航 ---------- */
.c28-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 120;
  padding: 14px clamp(12px, 3vw, 28px) 0;
  background: linear-gradient(180deg, rgba(11, 18, 32, 0.94) 0%, rgba(11, 18, 32, 0.58) 62%, rgba(11, 18, 32, 0) 100%);
  pointer-events: none;
}

.c28-header__shell {
  pointer-events: auto;
  position: relative;
  width: min(1360px, 100%);
  margin-inline: auto;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 26px);
  padding: 10px 16px 12px;
  border: 1px solid var(--c28-hair);
  border-radius: 999px;
  background: rgba(17, 28, 51, 0.76);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  backdrop-filter: blur(16px) saturate(140%);
  box-shadow: 0 22px 48px -30px rgba(0, 0, 0, 0.98), inset 0 1px 0 rgba(247, 241, 229, 0.06);
}

.c28-header__progress {
  position: absolute;
  left: 26px;
  right: 26px;
  bottom: 5px;
  height: 2px;
  border-radius: 999px;
  background: rgba(247, 241, 229, 0.1);
  overflow: hidden;
}
.c28-header__bar {
  display: block;
  height: 100%;
  width: 0;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--c28-cyan), var(--c28-gold));
  transition: width 0.12s linear;
}

.c28-brand {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--c28-paper);
}
.c28-brand__mark {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-family: var(--c28-mono);
  font-size: 15px;
  font-weight: 700;
  color: #05231F;
  background: linear-gradient(140deg, var(--c28-cyan), #1FB6A8 62%, var(--c28-gold));
  transition: transform 0.2s var(--c28-ease);
}
.c28-brand:hover .c28-brand__mark { transform: translateY(-2px) rotate(-3deg); }
.c28-brand__text {
  display: grid;
  line-height: 1.15;
}
.c28-brand__name {
  font-size: 16.5px;
  font-weight: 800;
  letter-spacing: -0.01em;
}
.c28-brand__sub {
  font-family: var(--c28-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--c28-slate);
}

.c28-nav {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
}
.c28-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.c28-nav__link {
  display: block;
  padding: 9px 13px;
  border-radius: 999px;
  color: rgba(247, 241, 229, 0.76);
  font-size: 15px;
  font-weight: 500;
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.18s var(--c28-ease), color 0.18s var(--c28-ease), transform 0.18s var(--c28-ease), box-shadow 0.18s var(--c28-ease);
}
.c28-nav__link:hover {
  color: var(--c28-paper);
  background: rgba(57, 224, 208, 0.12);
  transform: translateY(-1px);
}
.c28-nav__link[aria-current="page"] {
  color: var(--c28-cyan);
  background: rgba(57, 224, 208, 0.14);
  box-shadow: inset 0 0 0 1px rgba(57, 224, 208, 0.45);
  font-weight: 600;
}

.c28-header__meta {
  flex: 0 0 auto;
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: 10px;
}

.c28-stamp {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 12px;
  border: 1px dashed rgba(230, 184, 92, 0.42);
  border-radius: 999px;
  background: rgba(230, 184, 92, 0.08);
  color: var(--c28-gold);
  font-family: var(--c28-mono);
  font-size: 12px;
  letter-spacing: 0.02em;
  white-space: nowrap;
}
.c28-stamp__dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--c28-gold);
  box-shadow: 0 0 0 3px rgba(230, 184, 92, 0.18);
  flex: 0 0 auto;
}

.c28-cta {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  background: var(--c28-coral);
  color: #2A0D06;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
  box-shadow: 0 14px 28px -16px rgba(255, 107, 74, 0.95);
  transition: transform 0.18s var(--c28-ease), background 0.18s var(--c28-ease), box-shadow 0.18s var(--c28-ease);
}
.c28-cta:hover {
  transform: translateY(-2px);
  background: #FF8368;
  box-shadow: 0 18px 34px -16px rgba(255, 107, 74, 1);
}

.c28-burger {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 9px 15px 9px 12px;
  border: 1px solid var(--c28-hair-strong);
  border-radius: 999px;
  background: rgba(247, 241, 229, 0.05);
  color: var(--c28-paper);
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.18s var(--c28-ease), background 0.18s var(--c28-ease), color 0.18s var(--c28-ease);
}
.c28-burger:hover {
  border-color: var(--c28-cyan);
  background: rgba(57, 224, 208, 0.1);
  color: var(--c28-cyan);
}
.c28-burger__bars {
  display: grid;
  gap: 4px;
  width: 16px;
}
.c28-burger__bars i {
  display: block;
  height: 1.5px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.2s var(--c28-ease);
}
.c28-header[data-open] .c28-burger__bars i:first-child {
  transform: translateY(2.75px) rotate(45deg);
}
.c28-header[data-open] .c28-burger__bars i:last-child {
  transform: translateY(-2.75px) rotate(-45deg);
}
.c28-burger__label {
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
}

/* ---------- 11. 页脚 ---------- */
.c28-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  border-top: 1px solid rgba(247, 241, 229, 0.1);
  background: var(--c28-ink-2);
  color: rgba(247, 241, 229, 0.72);
  font-size: 15px;
}
.c28-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--c28-cyan) 22%, var(--c28-gold) 64%, transparent);
  opacity: 0.55;
}

.c28-footer__grid {
  display: grid;
  grid-template-columns: minmax(240px, 1.5fr) repeat(3, minmax(120px, 1fr));
  gap: clamp(26px, 4vw, 54px);
  padding-block: clamp(40px, 5vw, 68px);
}

.c28-footer__brand { max-width: 36ch; }
.c28-footer__mark {
  width: 42px;
  height: 42px;
  border-radius: 13px;
  display: grid;
  place-items: center;
  margin-bottom: 14px;
  font-family: var(--c28-mono);
  font-size: 16px;
  font-weight: 700;
  color: #05231F;
  background: linear-gradient(140deg, var(--c28-cyan), #1FB6A8 62%, var(--c28-gold));
}
.c28-footer__name {
  margin: 0 0 6px;
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--c28-paper);
}
.c28-footer__desc {
  margin: 0 0 16px;
  font-size: 14.5px;
  line-height: 1.7;
  color: rgba(247, 241, 229, 0.6);
}
.c28-footer__stamp {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 6px 12px;
  border: 1px dashed rgba(230, 184, 92, 0.4);
  border-radius: 999px;
  background: rgba(230, 184, 92, 0.08);
  color: var(--c28-gold);
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
}
.c28-footer__contact {
  display: grid;
  gap: 7px;
  margin: 18px 0 0;
  font-size: 14px;
}
.c28-footer__row {
  display: flex;
  align-items: baseline;
  gap: 10px;
}
.c28-footer__key {
  flex: 0 0 auto;
  font-family: var(--c28-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--c28-slate);
}
.c28-footer__val {
  margin: 0;
  color: rgba(247, 241, 229, 0.8);
  word-break: break-word;
}

.c28-footer__title {
  margin: 0 0 14px;
  font-family: var(--c28-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--c28-cyan);
}
.c28-footer__list {
  display: grid;
  gap: 9px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.c28-footer__link {
  display: inline-block;
  padding: 2px 0;
  color: rgba(247, 241, 229, 0.72);
  font-size: 14.5px;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--c28-ease), transform 0.18s var(--c28-ease), border-color 0.18s var(--c28-ease);
}
.c28-footer__link:hover {
  color: var(--c28-cyan);
  transform: translateX(3px);
  border-bottom-color: rgba(57, 224, 208, 0.5);
}

.c28-footer__base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding-block: 20px 26px;
  border-top: 1px solid rgba(247, 241, 229, 0.1);
}
.c28-footer__copy {
  margin: 0;
  font-family: var(--c28-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--c28-slate);
}
.c28-totop {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 9px 16px;
  border: 1px solid var(--c28-hair-strong);
  border-radius: 999px;
  background: rgba(247, 241, 229, 0.04);
  color: var(--c28-paper);
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.18s var(--c28-ease), border-color 0.18s var(--c28-ease), background 0.18s var(--c28-ease), color 0.18s var(--c28-ease);
}
.c28-totop::before {
  content: "↑";
  font-family: var(--c28-mono);
  font-size: 13px;
  color: var(--c28-cyan);
}
.c28-totop:hover {
  transform: translateY(-2px);
  border-color: var(--c28-cyan);
  background: rgba(57, 224, 208, 0.1);
  color: var(--c28-cyan);
}

/* ---------- 12. 响应式：平板 ---------- */
@media (max-width: 1180px) {
  .c28-stamp { display: none; }
}

@media (max-width: 1024px) {
  .c28-brand__sub { display: none; }
  .c28-nav__link { padding: 8px 10px; font-size: 14px; }
  .c28-footer__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: clamp(24px, 4vw, 40px);
  }
  .c28-footer__brand { grid-column: 1 / -1; max-width: 46ch; }
}

/* ---------- 13. 响应式：移动抽屉导航 ---------- */
@media (max-width: 940px) {
  body { padding-top: 84px; }

  .c28-header__shell {
    border-radius: 20px;
    padding: 9px 12px 11px;
    gap: 10px;
  }

  .c28-header__progress { left: 16px; right: 16px; bottom: 4px; }

  .c28-burger { display: inline-flex; }

  .c28-nav {
    position: absolute;
    top: calc(100% + 10px);
    left: 0;
    right: 0;
    display: block;
    max-height: calc(100vh - 150px);
    overflow-y: auto;
    padding: 10px;
    border: 1px solid var(--c28-hair);
    border-radius: 20px;
    background: rgba(11, 18, 32, 0.97);
    -webkit-backdrop-filter: blur(18px) saturate(140%);
    backdrop-filter: blur(18px) saturate(140%);
    box-shadow: 0 30px 60px -34px rgba(0, 0, 0, 1);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.2s var(--c28-ease), transform 0.2s var(--c28-ease), visibility 0.2s linear;
  }
  .c28-header[data-open] .c28-nav {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .c28-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
  }
  .c28-nav__link {
    padding: 12px 14px;
    border-radius: 12px;
    font-size: 16px;
  }
  .c28-nav__link:hover { transform: none; }
  .c28-nav__link[aria-current="page"] { box-shadow: inset 3px 0 0 var(--c28-cyan); }
}

/* ---------- 14. 响应式：手机 ---------- */
@media (max-width: 640px) {
  body { font-size: 16px; }

  .c28-shell { width: calc(100% - 1.75rem); }

  .c28-brand__mark { width: 34px; height: 34px; border-radius: 11px; font-size: 13.5px; }
  .c28-brand__name { font-size: 15.5px; }

  .c28-cta { padding: 9px 14px; font-size: 12.5px; }
  .c28-burger { padding: 8px 12px 8px 10px; }
  .c28-burger__label { display: none; }

  .c28-footer__grid { grid-template-columns: 1fr; }
  .c28-footer__base { flex-direction: column; align-items: flex-start; }
  .c28-footer__copy { font-size: 12px; }
}

/* ---------- 15. 减少动态效果 ---------- */
@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;
  }

  .c28-card:hover,
  .c28-btn:hover,
  .c28-cta:hover,
  .c28-totop:hover,
  .c28-footer__link:hover,
  .c28-brand:hover .c28-brand__mark,
  .c28-nav__link:hover {
    transform: none;
  }

  .is-reveal-ready {
    opacity: 1;
    transform: none;
  }
}

/* ---------- 16. 打印 ---------- */
@media print {
  .c28-header,
  .c28-skip,
  .c28-totop { display: none !important; }

  body {
    padding-top: 0;
    background: #FFFFFF;
    color: #000000;
  }

  .c28-footer {
    background: #FFFFFF;
    color: #000000;
    border-top: 1px solid #999999;
  }
  .c28-footer::before { display: none; }
  .c28-footer__link,
  .c28-footer__val,
  .c28-footer__desc,
  .c28-footer__copy { color: #000000; }
  .c28-footer__name,
  .c28-footer__title { color: #000000; }
}