/* Castbot · 静态官网主样式
 * 设计参考：apple.com.cn 字体/排版/配色原则（暗色版）
 * 主题：默认深色（开发者工具调性），light 通过 prefers-color-scheme 自动切换
 * 字体栈：SF Pro Display → SF Pro Text → -apple-system → PingFang SC（中文首选）
 * 字重分级：400 regular / 500 medium（强调）/ 600 semibold（标题）/ 700 hero
 * 行高：1.47 body（Apple 标准），1.07-1.2 标题
 * 字距：-0.022em body（Apple 中文紧字距）
 */

:root {
  /* Dark theme (default) — 保留原终端绿 CTA + 暗色基底 */
  --bg-primary:   #0a0e1a;
  --bg-elevated:  #131829;
  --bg-card:      #161c2e;
  --text-primary: #f3f6fb;
  --text-muted:   #a8b3c8;
  --accent:       #00ff9d;   /* 终端绿 - CTA */
  --accent-hover: #00e589;
  --accent-2:     #4d7cff;   /* 调度蓝 - 状态色 */
  --border:       #232b40;
  --shadow:       0 4px 20px rgba(0, 0, 0, 0.3);

  /* Apple 圆角分级（卡片 18，按钮 pill，小元素 8-12） */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-pill: 980px;
  --max-width: 1120px;
  --gutter: clamp(16px, 4vw, 32px);

  /* Apple 字体栈：SF Pro → 苹方-简 → Microsoft YaHei fallback */
  --font-sans:
    "SF Pro Display",
    "SF Pro Text",
    -apple-system,
    BlinkMacSystemFont,
    "PingFang SC",
    "Helvetica Neue",
    "Microsoft YaHei",
    "Source Han Sans SC",
    system-ui,
    "Segoe UI", Roboto, sans-serif;

  /* Apple 字号比例（body 17px 标杆） */
  --fs-xs:   12px;
  --fs-sm:   14px;
  --fs-base: 17px;
  --fs-md:   19px;
  --fs-lg:   24px;
  --fs-xl:   32px;
  --fs-2xl:  48px;
  --fs-3xl:  64px;

  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

@media (prefers-color-scheme: light) {
  :root {
    /* Apple light theme 配色（apple.com.cn 标准） */
    --bg-primary:   #ffffff;
    --bg-elevated:  #f5f5f7;
    --bg-card:      #ffffff;
    --text-primary: #1d1d1f;       /* Apple 文字主色 */
    --text-muted:   #6e6e73;       /* Apple 文字次色 */
    --accent:       #0066cc;       /* Apple 蓝 */

  /* 2026-08-24 a11y: 浅色模式下 CTA 按钮文字改白（#0066cc 上 #04130a 仅 ~3:1 不达标） */
  .tg-btn, .nav .tg-btn, .nav .tg-btn:hover,
  .btn-primary, .btn-primary:hover,
  #generate-invite-btn, #copy-invite-btn { color: #ffffff; }
  #generate-invite-btn, #copy-invite-btn { color: #ffffff !important; }  /* 覆盖内联 style */
    --accent-hover: #0044aa;
    --accent-2:     #2d5cd6;
    --border:       #d2d2d7;
    --shadow:       0 4px 20px rgba(15, 23, 42, 0.06);
  }
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  padding: 0;
  background: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: var(--fs-base);             /* Apple 标杆 17px */
  font-weight: 400;                      /* Apple default regular */
  line-height: 1.47059;                  /* Apple 标准 body 行高 */
  letter-spacing: -0.022em;              /* Apple 中文紧字距 */
  font-feature-settings: "kern" 1;       /* 中文 kerning */
  font-synthesis-weight: none;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-locale: zh-CN;
}

/* ---------- 标题分级（Apple semibold） ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;                      /* semibold，不是 bold */
  letter-spacing: -0.015em;
  line-height: 1.1;
  color: var(--text-primary);
}
h1 { font-size: var(--fs-3xl); letter-spacing: -0.025em; }
h2 { font-size: var(--fs-2xl); }
h3 { font-size: var(--fs-xl); }
h4 { font-size: var(--fs-md); }
h5 { font-size: var(--fs-base); }

/* ---------- 强调（Apple medium 不是 bold） ---------- */
strong, em, .emphasis {
  font-weight: 500;
  font-style: normal;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--accent-hover); text-decoration: underline; }

img, svg { max-width: 100%; height: auto; }

p {
  font-weight: 400;
  line-height: 1.5;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 26, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}
@media (prefers-color-scheme: light) {
  .site-header { background: rgba(255, 255, 255, 0.85); }
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  padding-bottom: 14px;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text-primary);
  font-weight: 600;                      /* semibold */
  font-size: 17px;
  letter-spacing: -0.015em;
}
.brand:hover { color: var(--text-primary); text-decoration: none; }

.brand-mark {
  width: 24px;
  height: 24px;
  color: var(--accent);
  flex-shrink: 0;
}

.nav {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
}
.nav a {
  color: var(--text-muted);
  font-size: var(--fs-sm);
  font-weight: 400;
}
.nav a:hover { color: var(--text-primary); text-decoration: none; }

.tg-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--accent);
  color: #04130a;
  padding: 10px 18px;
  border-radius: var(--radius-pill);     /* Apple pill 形状 */
  font-weight: 500;                      /* Apple CTA medium */
  font-size: var(--fs-sm);
  border: 0;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease;
}
.tg-btn:hover { background: var(--accent-hover); color: #04130a; text-decoration: none; }
.tg-btn:active { transform: translateY(1px); }

/* Override .nav a color for tg-btn */
.nav .tg-btn {
  color: #04130a;
}
.nav .tg-btn:hover {
  color: #04130a;
}

/* ---------- Main ---------- */
main {
  flex: 1 0 auto;
}

section {
  padding: clamp(48px, 8vw, 96px) 0;
  border-bottom: 1px solid var(--border);
}
section:last-of-type { border-bottom: 0; }

.section-title {
  font-size: clamp(var(--fs-lg), 4vw, var(--fs-2xl));
  font-weight: 600;                      /* semibold */
  margin: 0 0 12px 0;
  letter-spacing: -0.02em;
  line-height: 1.1;
}
.section-lead {
  color: var(--text-muted);
  font-size: var(--fs-md);
  font-weight: 400;
  margin: 0 0 40px 0;
  max-width: 60ch;
  line-height: 1.47;
}

/* ---------- Hero ---------- */
.hero {
  text-align: center;
  padding: clamp(64px, 12vw, 128px) 0 clamp(48px, 8vw, 80px);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute;
  inset: -50% -10% auto -10%;
  height: 80%;
  background:
    radial-gradient(60% 50% at 50% 0%, rgba(0, 255, 157, 0.10), transparent 70%),
    radial-gradient(40% 40% at 70% 10%, rgba(77, 124, 255, 0.08), transparent 70%);
  pointer-events: none;
  z-index: 0;
}
.hero .container { position: relative; z-index: 1; }

.hero h1 {
  font-size: clamp(36px, 7vw, var(--fs-3xl));
  line-height: 1.07;                     /* Apple hero 行高 */
  letter-spacing: -0.025em;
  margin: 0 auto 20px;
  max-width: 18ch;
  font-weight: 600;                      /* semibold，Apple hero 不用 bold */
}
.hero .sub {
  font-size: var(--fs-md);
  color: var(--text-muted);
  font-weight: 400;
  max-width: 56ch;
  margin: 0 auto 32px;
  line-height: 1.47;
}

.cta-row {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}
.cta-row > * { width: 100%; max-width: 320px; }

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--accent);
  color: #04130a;
  padding: 14px 28px;
  border-radius: var(--radius-pill);     /* Apple pill */
  font-weight: 500;                      /* Apple CTA medium */
  font-size: var(--fs-base);
  min-height: 52px;
  border: 0;
  cursor: pointer;
  transition: background 0.15s ease, transform 0.1s ease, box-shadow 0.2s ease;
  box-shadow: 0 8px 24px rgba(0, 255, 157, 0.20);
  letter-spacing: -0.01em;
}
.btn-primary:hover {
  background: var(--accent-hover);
  color: #04130a;
  box-shadow: 0 12px 32px rgba(0, 255, 157, 0.30);
  text-decoration: none;
}
.btn-primary:active { transform: translateY(1px); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  color: var(--text-muted);
  padding: 12px 20px;
  font-size: var(--fs-sm);
  font-weight: 400;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  background: transparent;
  cursor: pointer;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.btn-secondary:hover {
  color: var(--text-primary);
  border-color: var(--accent);
  text-decoration: none;
}

/* ---------- Trust bar ---------- */
.trust-bar {
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
}
.trust-bar ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px 28px;
  font-size: var(--fs-sm);
  font-weight: 400;
  color: var(--text-muted);
}
.trust-bar li {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.trust-bar li::before {
  content: "";
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  display: inline-block;
}

/* ---------- Selling points / cards ---------- */
.grid-3 {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}
@media (min-width: 760px) {
  .grid-3 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);       /* Apple 18px 圆角 */
  padding: 32px 28px;                    /* Apple 大量留白 */
  transition: border-color 0.2s ease, transform 0.2s ease;
}
.card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}
.card .icon {
  width: 36px;
  height: 36px;
  color: var(--accent);
  margin-bottom: 18px;
}
.card h3 {
  margin: 0 0 10px 0;
  font-size: var(--fs-md);
  font-weight: 600;                      /* semibold */
  letter-spacing: -0.015em;
}
.card p {
  margin: 0;
  color: var(--text-muted);
  font-size: var(--fs-base);
  font-weight: 400;
  line-height: 1.47;
}

/* ---------- Steps strip ---------- */
.steps {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  counter-reset: step;
}
@media (min-width: 760px) {
  .steps { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
}
.step {
  position: relative;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 24px;
  counter-increment: step;
}
.step::before {
  content: counter(step);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--accent);
  color: #04130a;
  border-radius: 50%;
  font-weight: 600;
  font-size: var(--fs-sm);
  margin-bottom: 14px;
}
.step h4 {
  margin: 0 0 8px 0;
  font-size: var(--fs-base);
  font-weight: 600;
}
.step p {
  margin: 0;
  font-size: var(--fs-sm);
  font-weight: 400;
  color: var(--text-muted);
  line-height: 1.47;
}

/* ---------- Sample posts ---------- */
.sample-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}
@media (min-width: 760px) {
  .sample-grid { grid-template-columns: repeat(3, 1fr); }
}
.sample {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px 20px;
  font-size: var(--fs-sm);
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.sample .tag {
  display: inline-block;
  font-size: var(--fs-xs);
  color: var(--accent-2);
  background: rgba(77, 124, 255, 0.12);
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  align-self: flex-start;
  font-weight: 500;
  letter-spacing: -0.005em;
}
.sample .body {
  color: var(--text-primary);
  line-height: 1.5;
  white-space: pre-wrap;
  font-size: var(--fs-sm);
}
.sample .meta {
  color: var(--text-muted);
  font-size: var(--fs-xs);
}

/* ---------- Final CTA ---------- */
.final-cta {
  text-align: center;
  background:
    radial-gradient(60% 60% at 50% 50%, rgba(0, 255, 157, 0.08), transparent 70%);
}
.final-cta h2 {
  font-size: clamp(var(--fs-lg), 4vw, var(--fs-2xl));
  font-weight: 600;
  margin: 0 0 24px 0;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

/* ---------- Footer ---------- */
.site-footer {
  flex-shrink: 0;
  border-top: 1px solid var(--border);
  background: var(--bg-elevated);
  padding: 40px 0 24px;
  font-size: var(--fs-sm);
  font-weight: 400;
  color: var(--text-muted);
}
.site-footer .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
}
@media (min-width: 720px) {
  .site-footer .container { grid-template-columns: 2fr 1fr 1fr; }
}
.site-footer h5 {
  color: var(--text-primary);
  font-size: var(--fs-xs);
  font-weight: 600;
  margin: 0 0 12px 0;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.site-footer .copyright {
  border-top: 1px solid var(--border);
  margin-top: 24px;
  padding-top: 20px;
  text-align: center;
  font-size: var(--fs-xs);
}
.site-footer .copyright a {
  margin: 0 8px;
}

/* ---------- Article (compliance / faq / contact) ---------- */
.article {
  max-width: 760px;
  margin: 0 auto;
}
.article h1 {
  font-size: clamp(var(--fs-xl), 5vw, 44px);
  font-weight: 600;
  letter-spacing: -0.025em;
  margin: 0 0 8px 0;
  line-height: 1.1;
}
.article .meta {
  color: var(--text-muted);
  font-size: var(--fs-sm);
  margin-bottom: 32px;
}
.article h2 {
  font-size: var(--fs-lg);
  font-weight: 600;
  margin: 36px 0 12px;
  letter-spacing: -0.015em;
  line-height: 1.2;
}
.article h3 {
  font-size: var(--fs-base);
  font-weight: 600;
  margin: 24px 0 8px;
}
.article p, .article ul, .article ol {
  margin: 0 0 16px 0;
  line-height: 1.5;
  font-weight: 400;
  color: var(--text-primary);
  font-size: var(--fs-base);
}
.article ul, .article ol { padding-left: 1.4em; }
.article li { margin-bottom: 6px; }
.article strong { color: var(--text-primary); font-weight: 500; }  /* Apple medium 强调 */
.article .callout {
  background: var(--bg-elevated);
  border-left: 3px solid var(--accent);
  padding: 14px 18px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 16px 0;
  font-size: var(--fs-sm);
}

/* ---------- 代码块 + 复制按钮 ---------- */
.article pre {
  position: relative;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 56px 14px 16px;
  margin: 8px 0 16px;
  overflow-x: auto;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: var(--fs-sm);
  line-height: 1.55;
  color: var(--text-primary);
}
.article pre code {
  background: transparent;
  padding: 0;
  font: inherit;
  color: inherit;
  font-size: inherit;
}
.article pre .copy-btn {
  position: absolute;
  top: 8px;
  right: 8px;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  font-size: 12px;
  font-family: inherit;
  background: rgba(128, 128, 128, 0.12);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease, background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
  user-select: none;
}
.article pre:hover .copy-btn,
.article pre:focus-within .copy-btn,
.article pre .copy-btn:focus-visible { opacity: 1; }
.article pre .copy-btn:hover {
  background: var(--accent);
  color: var(--bg-primary);
  border-color: var(--accent);
}
.article pre .copy-btn.is-copied {
  background: #10b981;
  color: #ffffff;
  border-color: #10b981;
  opacity: 1;
}
@media (hover: none) {
  /* 触屏设备没有 hover，始终显示复制按钮 */
  .article pre .copy-btn { opacity: 1; }
}

/* PowerShell / shell 提示徽章 */
.shell-hint {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  margin: 0 0 8px 0;
  font-size: 12px;
  font-family: inherit;
  background: rgba(77, 124, 255, 0.12);
  color: var(--accent-2);
  border: 1px solid rgba(77, 124, 255, 0.35);
  border-radius: var(--radius-pill);
  vertical-align: middle;
}
.shell-hint--ps {
  background: rgba(0, 122, 204, 0.16);
  color: #5ba7e6;
  border-color: rgba(0, 122, 204, 0.4);
}
.shell-hint--bash {
  background: rgba(0, 0, 0, 0.18);
  color: var(--text-muted);
  border-color: var(--border);
}
@media (prefers-color-scheme: light) {
  .shell-hint--ps {
    background: rgba(0, 82, 153, 0.08);
    color: #0066cc;
    border-color: rgba(0, 82, 153, 0.3);
  }
}

/* 安装命令 callout（docs.html 用） */
.install-cmd-list {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  margin: 12px 0 16px;
}
.install-cmd-list ul { margin: 0; padding-left: 0; list-style: none; }
.install-cmd-list li {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 6px 0;
  margin-bottom: 0;
}
.install-cmd-list li + li { border-top: 1px solid var(--border); padding-top: 10px; margin-top: 4px; }
.install-cmd-list .cmd-label {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  min-width: 110px;
  font-weight: 500;
}
.install-cmd-list code {
  flex: 1;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  background: var(--bg-primary);
  color: var(--text-primary);
  padding: 6px 36px 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
  position: relative;
  display: inline-block;
  word-break: break-all;
}
.copy-btn-inline {
  flex: 0 0 auto;
  padding: 4px 10px;
  font-size: 12px;
  font-family: inherit;
  background: rgba(128, 128, 128, 0.12);
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
  user-select: none;
}
.copy-btn-inline:hover { background: var(--accent); color: var(--bg-primary); border-color: var(--accent); }
.copy-btn-inline.is-copied { background: #10b981; color: #ffffff; border-color: #10b981; }

/* ---------- FAQ ---------- */
details.faq-item {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 0;
  margin-bottom: 12px;
  overflow: hidden;
}
details.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 20px 24px;
  font-weight: 500;                      /* Apple medium */
  font-size: var(--fs-base);
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  color: var(--text-primary);
  letter-spacing: -0.015em;
}
details.faq-item summary::-webkit-details-marker { display: none; }
details.faq-item summary::after {
  content: "+";
  color: var(--accent);
  font-size: var(--fs-lg);
  font-weight: 400;
  flex-shrink: 0;
  transition: transform 0.2s ease;
}
details.faq-item[open] summary::after { content: "−"; }
details.faq-item .answer {
  padding: 0 24px 20px;
  color: var(--text-muted);
  font-size: var(--fs-base);
  font-weight: 400;
  line-height: 1.5;
}

/* ---------- Anchor scroll offset (sticky header 不遮挡) ---------- */
:target,
h2[id], h3[id] {
  scroll-margin-top: 90px;
}

/* ---------- Docs knowledge base ---------- */
.docs-toc {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  margin: 24px 0 8px;
}
.docs-toc h2 {
  font-size: var(--fs-base);
  font-weight: 600;
  margin: 0 0 12px;
}
.docs-toc ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}
.docs-toc a {
  font-size: var(--fs-sm);
  color: var(--text-muted);
  font-weight: 400;
}
.docs-toc a:hover { color: var(--accent); text-decoration: none; }

.qa-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
}
.qa-item:last-of-type { border-bottom: 0; }
.qa-item h3 {
  margin: 0 0 10px;
  font-size: var(--fs-md);
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.015em;
}
.qa-item .answer p { margin: 0 0 12px; }
.qa-item .answer p:last-child { margin-bottom: 0; }
.qa-item ul, .qa-item ol {
  color: var(--text-muted);
  margin: 0 0 12px;
  line-height: 1.6;
}
.qa-item li { margin-bottom: 4px; }
.qa-item code {
  background: var(--bg-card);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-size: .88em;
  color: var(--text-primary);
}

/* ---------- "更多" link (FAQ → Docs 同分类) ---------- */
.more-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin: 14px 0 28px;
  padding: 8px 18px;
  font-size: var(--fs-sm);
  font-weight: 500;
  color: var(--accent);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  background: transparent;
  transition: border-color 0.15s ease, background 0.15s ease, color 0.15s ease;
  letter-spacing: -0.01em;
}
.more-link:hover {
  border-color: var(--accent);
  background: rgba(0, 255, 157, 0.06);
  color: var(--accent);
  text-decoration: none;
}
@media (prefers-color-scheme: light) {
  .more-link:hover { background: rgba(0, 102, 204, 0.06); }
}

/* ---------- 404 ---------- */
.notfound {
  text-align: center;
  padding: 80px 0;
}
.notfound .code {
  font-size: clamp(72px, 18vw, 140px);
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 8px;
}
.notfound p {
  color: var(--text-muted);
  font-size: var(--fs-md);
  margin-bottom: 28px;
}

/* ---------- Visually hidden ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0);
  white-space: nowrap; border: 0;
}


/* ---------- 2026-08-24 a11y: 页脚链接下划线（不仅靠颜色区分） ---------- */
.site-footer .copyright a {
  text-decoration: underline;
  text-underline-offset: 3px;
}