/* ==========================================================================
   智涌 TechTide — 设计系统
   白底 · 蓝色点缀 · 深灰文字 · 简约现代
   ========================================================================== */

:root {
  /* 色板 */
  --blue: #2563eb;
  --blue-dark: #1e40af;
  --blue-deep: #172554;
  --blue-soft: #dbeafe;
  --blue-tint: #eff6ff;
  --cyan: #0ea5e9;

  --ink: #0f172a;        /* 主文字（深灰近黑） */
  --gray: #475569;       /* 次级文字 */
  --muted: #94a3b8;      /* 弱化文字 */
  --line: #e2e8f0;       /* 边框 */

  --bg: #ffffff;
  --bg-soft: #f8fafc;

  /* 字体 */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SF Mono", ui-monospace, Menlo, monospace;

  /* 布局 */
  --container: 1160px;
  --header-h: 72px;
  --radius: 16px;
  --radius-sm: 10px;

  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .05);
  --shadow-md: 0 8px 24px -8px rgba(15, 23, 42, .12);
  --shadow-lg: 0 20px 48px -16px rgba(37, 99, 235, .22);

  --ease: cubic-bezier(.22, .61, .36, 1);
}

/* ------------------------------ 基础重置 ------------------------------ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img, svg { display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
ul { list-style: none; }
dd, dt { margin: 0; }

::selection { background: var(--blue); color: #fff; }

.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: 24px;
}

/* ------------------------------ 通用按钮 ------------------------------ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  border-radius: 999px;
  transition: transform .25s var(--ease), box-shadow .25s var(--ease),
              background-color .25s var(--ease), color .25s var(--ease),
              border-color .25s var(--ease);
  white-space: nowrap;
}
.btn:active { transform: scale(.97); }

.btn-primary {
  background: var(--blue);
  color: #fff;
  padding: 12px 26px;
  box-shadow: 0 8px 20px -8px rgba(37, 99, 235, .55);
}
.btn-primary:hover { background: var(--blue-dark); transform: translateY(-2px); box-shadow: 0 12px 26px -8px rgba(37, 99, 235, .6); }

.btn-ghost {
  padding: 12px 26px;
  color: var(--gray);
  border: 1.5px solid var(--line);
  background: rgba(255, 255, 255, .7);
  backdrop-filter: blur(6px);
}
.btn-ghost:hover { color: var(--blue); border-color: var(--blue); transform: translateY(-2px); }

.btn-light {
  background: #fff;
  color: var(--blue-dark);
  padding: 12px 28px;
  box-shadow: 0 8px 20px -8px rgba(2, 6, 23, .5);
}
.btn-light:hover { transform: translateY(-2px); box-shadow: 0 12px 26px -8px rgba(2, 6, 23, .55); }

.btn-sm { padding: 8px 18px; font-size: .9rem; }
.btn-lg { padding: 14px 30px; font-size: 1.02rem; }

/* ------------------------------ 顶部进度条 ------------------------------ */
.progress-bar {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  width: 0;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  z-index: 120;
  transition: width .1s linear;
}

/* ------------------------------ 导航 ------------------------------ */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  z-index: 100;
  background: rgba(255, 255, 255, .78);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid transparent;
  transition: border-color .3s var(--ease), box-shadow .3s var(--ease), background .3s var(--ease);
}
.site-header.scrolled {
  border-bottom-color: var(--line);
  box-shadow: 0 4px 24px -12px rgba(15, 23, 42, .12);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo { display: inline-flex; align-items: center; gap: 10px; }
.logo-mark svg { border-radius: 9px; box-shadow: 0 4px 12px -4px rgba(37, 99, 235, .5); transition: transform .3s var(--ease); }
.logo:hover .logo-mark svg { transform: rotate(-8deg) scale(1.05); }
.logo-text { font-size: 1.22rem; font-weight: 800; letter-spacing: .02em; }
.logo-text small {
  font-size: .72rem;
  font-weight: 600;
  color: var(--blue);
  margin-left: 6px;
  letter-spacing: .14em;
  vertical-align: 2px;
}

.main-nav { display: flex; align-items: center; gap: 6px; }
.nav-link {
  position: relative;
  padding: 8px 14px;
  font-size: .94rem;
  font-weight: 500;
  color: var(--gray);
  border-radius: 8px;
  transition: color .2s var(--ease);
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 14px; right: 14px; bottom: 4px;
  height: 2px;
  border-radius: 2px;
  background: var(--blue);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .3s var(--ease);
}
.nav-link:hover { color: var(--ink); }
.nav-link:hover::after, .nav-link.active::after { transform: scaleX(1); }
.nav-link.active { color: var(--blue); font-weight: 600; }
.nav-cta { margin-left: 10px; }

.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 42px; height: 42px;
  border-radius: 10px;
  border: 1px solid var(--line);
  padding: 10px;
}
.menu-toggle span {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--ink);
  transition: transform .3s var(--ease), opacity .3s var(--ease);
}
.menu-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ------------------------------ Hero ------------------------------ */
.hero {
  position: relative;
  min-height: 100vh;
  min-height: 100svh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background:
    radial-gradient(1200px 500px at 85% -10%, rgba(37, 99, 235, .07), transparent 60%),
    radial-gradient(900px 420px at 8% 110%, rgba(14, 165, 233, .06), transparent 60%),
    var(--bg);
  padding: calc(var(--header-h) + 40px) 0 80px;
}

#particleCanvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(70px);
  z-index: 0;
  pointer-events: none;
  opacity: .5;
}
.orb-a {
  width: 480px; height: 480px;
  right: -140px; top: -120px;
  background: radial-gradient(circle at 30% 30%, rgba(37, 99, 235, .22), transparent 65%);
  animation: drift 16s ease-in-out infinite alternate;
}
.orb-b {
  width: 380px; height: 380px;
  left: -120px; bottom: -100px;
  background: radial-gradient(circle at 60% 40%, rgba(14, 165, 233, .18), transparent 65%);
  animation: drift 20s ease-in-out infinite alternate-reverse;
}
@keyframes drift {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(-40px, 30px) scale(1.08); }
}

.hero-inner { position: relative; z-index: 1; width: 100%; }

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: .82rem;
  font-weight: 600;
  letter-spacing: .18em;
  color: var(--blue);
  background: var(--blue-tint);
  border: 1px solid var(--blue-soft);
  padding: 8px 18px;
  border-radius: 999px;
  margin-bottom: 28px;
}
.pulse-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--blue);
  box-shadow: 0 0 0 0 rgba(37, 99, 235, .45);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgba(37, 99, 235, .45); }
  70%  { box-shadow: 0 0 0 9px rgba(37, 99, 235, 0); }
  100% { box-shadow: 0 0 0 0 rgba(37, 99, 235, 0); }
}

.hero-title {
  font-size: clamp(2.5rem, 6.2vw, 4.3rem);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -.02em;
  margin-bottom: 24px;
}
.grad-text {
  background: linear-gradient(100deg, var(--blue) 10%, var(--cyan) 90%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  max-width: 560px;
  font-size: 1.12rem;
  color: var(--gray);
  margin-bottom: 36px;
}

.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 56px; }

.hero-stats {
  display: flex;
  gap: clamp(28px, 6vw, 72px);
  padding-top: 28px;
  border-top: 1px solid var(--line);
  max-width: 560px;
}
.stat-num {
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  font-weight: 800;
  color: var(--ink);
  letter-spacing: -.02em;
  font-variant-numeric: tabular-nums;
}
.stat dd { color: var(--muted); font-size: .88rem; margin-top: 2px; }

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  z-index: 1;
  opacity: .55;
  transition: opacity .3s var(--ease);
}
.scroll-hint:hover { opacity: 1; }
.mouse {
  display: block;
  width: 24px; height: 38px;
  border: 2px solid var(--gray);
  border-radius: 14px;
  position: relative;
}
.mouse::before {
  content: "";
  position: absolute;
  left: 50%; top: 7px;
  width: 4px; height: 8px;
  margin-left: -2px;
  border-radius: 4px;
  background: var(--blue);
  animation: wheel 1.8s ease-in-out infinite;
}
@keyframes wheel {
  0%   { transform: translateY(0); opacity: 1; }
  70%  { transform: translateY(10px); opacity: 0; }
  100% { transform: translateY(0); opacity: 0; }
}

/* ------------------------------ 通用 Section ------------------------------ */
.section { padding: 96px 0; }
.section-soft { background: var(--bg-soft); }

.section-head { max-width: 640px; margin-bottom: 48px; }
.section-head-row {
  max-width: none;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
}

.section-eyebrow {
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--blue);
  margin-bottom: 10px;
}
.section-title {
  font-size: clamp(1.7rem, 3.4vw, 2.3rem);
  font-weight: 800;
  letter-spacing: -.01em;
  margin-bottom: 12px;
}
.section-desc { color: var(--gray); font-size: 1.02rem; }

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-weight: 600;
  color: var(--blue);
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
  transition: border-color .25s var(--ease), gap .25s var(--ease);
}
.link-arrow:hover { border-bottom-color: var(--blue); gap: 10px; }

/* ------------------------------ 卡片通用 ------------------------------ */
.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: transform .35s var(--ease), box-shadow .35s var(--ease), border-color .35s var(--ease);
}
.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-md);
  border-color: #cbd5e1;
}

.card-body { padding: 22px 24px 24px; }
.card-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: .82rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  margin-bottom: 10px;
}
.card-meta .dot { opacity: .6; }
.card-meta time { color: var(--blue); font-weight: 600; }

.card-title { font-size: 1.42rem; line-height: 1.4; margin-bottom: 10px; letter-spacing: -.01em; }
.card-title-sm { font-size: 1.08rem; line-height: 1.5; margin-bottom: 8px; letter-spacing: -.005em; }
.card-title a, .card-title-sm a { transition: color .2s var(--ease); }
.card-title a:hover, .card-title-sm a:hover { color: var(--blue); }

.card-excerpt { color: var(--gray); font-size: .94rem; margin-bottom: 18px; }

.card-foot {
  display: flex;
  align-items: center;
  gap: 10px;
}
.author-name { font-size: .88rem; font-weight: 600; color: var(--gray); }
.read-more {
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: .88rem;
  font-weight: 600;
  color: var(--blue);
  transition: gap .25s var(--ease);
}
.read-more:hover { gap: 9px; }

.avatar { border-radius: 50%; }
.avatar-xs { width: 28px; height: 28px; }

/* ------------------------------ 封面（纯 CSS 渐变） ------------------------------ */
.cover {
  position: relative;
  display: flex;
  align-items: flex-start;
  padding: 18px;
  overflow: hidden;
  transition: filter .35s var(--ease);
}
.cover-ratio { aspect-ratio: 16 / 9; }
.card:hover .cover { filter: saturate(1.15) brightness(1.03); }

/* 大图封面 */
.cover-llm      { background: linear-gradient(135deg, #1e3a8a 0%, #2563eb 55%, #38bdf8 130%); }
.cover-app      { background: linear-gradient(135deg, #0ea5e9 0%, #4f46e5 120%); }
.cover-frontend { background: linear-gradient(135deg, #2563eb 0%, #06b6d4 120%); }
.cover-tools    { background: linear-gradient(135deg, #0f172a 0%, #334155 80%, #475569 120%); }
.cover-paper    { background: linear-gradient(135deg, #4f46e5 0%, #2563eb 120%); }
.cover-industry { background: linear-gradient(135deg, #0891b2 0%, #1e40af 120%); }

/* 点阵纹理 */
.cover::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, .16) 1px, transparent 1.4px);
  background-size: 20px 20px;
  mask-image: linear-gradient(120deg, rgba(0,0,0,.9), transparent 65%);
  -webkit-mask-image: linear-gradient(120deg, rgba(0,0,0,.9), transparent 65%);
}

.cover-ring {
  position: absolute;
  right: -46px; bottom: -66px;
  width: 190px; height: 190px;
  border: 26px solid rgba(255, 255, 255, .12);
  border-radius: 50%;
  transition: transform .5s var(--ease);
}
.card:hover .cover-ring { transform: translate(-8px, -8px) rotate(8deg); }

.cover-sm {
  position: relative;
  display: flex;
  align-items: flex-start;
  padding: 16px;
  aspect-ratio: 21 / 9;
  overflow: hidden;
}
.cover-sm::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, .16) 1px, transparent 1.4px);
  background-size: 18px 18px;
  mask-image: linear-gradient(120deg, rgba(0,0,0,.9), transparent 70%);
  -webkit-mask-image: linear-gradient(120deg, rgba(0,0,0,.9), transparent 70%);
}
.featured-sm .cover-sm { border-radius: 0; }

.cover-tag {
  position: relative;
  z-index: 1;
  font-size: .74rem;
  font-weight: 700;
  letter-spacing: .08em;
  color: #fff;
  background: rgba(255, 255, 255, .18);
  border: 1px solid rgba(255, 255, 255, .35);
  backdrop-filter: blur(4px);
  padding: 5px 12px;
  border-radius: 999px;
}

/* ------------------------------ 精选文章布局 ------------------------------ */
.featured-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 24px;
  align-items: stretch;
}
.featured-main .cover { aspect-ratio: 16 / 10; }
.featured-main .card-body { padding: 28px 30px 30px; }
.featured-main .card-excerpt { font-size: 1rem; }

.featured-side {
  display: grid;
  grid-template-rows: 1fr 1fr;
  gap: 24px;
}
.featured-sm { display: flex; flex-direction: column; }
.featured-sm .card-body { padding: 18px 20px 20px; }
.featured-sm .card-excerpt { margin-bottom: 0; font-size: .9rem; }

/* ------------------------------ 分类导航 ------------------------------ */
.category-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.category-card {
  text-align: left;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px 22px;
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-areas:
    "icon  count"
    "name  count"
    "desc  count";
  column-gap: 12px;
  row-gap: 4px;
  box-shadow: var(--shadow-sm);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease), border-color .3s var(--ease);
}
.category-card:hover {
  transform: translateY(-4px);
  border-color: var(--blue);
  box-shadow: var(--shadow-lg);
}
.category-card.active { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft), var(--shadow-md); }

.cat-icon {
  grid-area: icon;
  width: 46px; height: 46px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  margin-bottom: 14px;
  color: #fff;
}
.icon-llm      { background: linear-gradient(135deg, #1e3a8a, #2563eb); }
.icon-app      { background: linear-gradient(135deg, #0ea5e9, #4f46e5); }
.icon-frontend { background: linear-gradient(135deg, #2563eb, #06b6d4); }
.icon-tools    { background: linear-gradient(135deg, #0f172a, #475569); }
.icon-paper    { background: linear-gradient(135deg, #4f46e5, #2563eb); }
.icon-industry { background: linear-gradient(135deg, #0891b2, #1e40af); }

.cat-name { grid-area: name; font-size: 1.12rem; font-weight: 700; }
.cat-desc { grid-area: desc; font-size: .85rem; color: var(--muted); }
.cat-count {
  grid-area: count;
  align-self: center;
  font-size: .8rem;
  font-weight: 700;
  color: var(--blue);
  background: var(--blue-tint);
  border: 1px solid var(--blue-soft);
  padding: 4px 12px;
  border-radius: 999px;
  white-space: nowrap;
}

/* ------------------------------ 最新文章 ------------------------------ */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 14px;
}
.filter-chip {
  padding: 9px 20px;
  border-radius: 999px;
  border: 1.5px solid var(--line);
  background: #fff;
  color: var(--gray);
  font-size: .9rem;
  font-weight: 600;
  transition: all .25s var(--ease);
}
.filter-chip:hover { border-color: var(--blue); color: var(--blue); transform: translateY(-1px); }
.filter-chip.active {
  background: var(--blue);
  border-color: var(--blue);
  color: #fff;
  box-shadow: 0 6px 16px -6px rgba(37, 99, 235, .55);
}

.filter-status {
  font-size: .85rem;
  color: var(--muted);
  margin-bottom: 26px;
  font-variant-numeric: tabular-nums;
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.article-card.is-hidden { display: none; }
.article-card { animation: cardIn .45s var(--ease) both; }
@keyframes cardIn {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

.article-card .card-body { padding: 20px 22px 22px; }
.article-card .card-excerpt {
  margin-bottom: 16px;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.empty-tip {
  text-align: center;
  color: var(--muted);
  padding: 56px 0;
  border: 1.5px dashed var(--line);
  border-radius: var(--radius);
}

/* ------------------------------ 热门话题 ------------------------------ */
.topics-wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}
.topic-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 12px 22px;
  border-radius: 999px;
  background: #fff;
  border: 1.5px solid var(--line);
  font-weight: 600;
  font-size: .95rem;
  color: var(--gray);
  transition: all .25s var(--ease);
}
.topic-pill:hover {
  border-color: var(--blue);
  color: var(--blue);
  transform: translateY(-3px);
  box-shadow: 0 10px 22px -10px rgba(37, 99, 235, .4);
}
.topic-top { border-color: var(--blue-soft); background: var(--blue-tint); }
.topic-top:hover { background: var(--blue-soft); }

.topic-rank {
  font-family: var(--font-mono);
  font-size: .8rem;
  font-weight: 700;
  color: var(--blue);
}
.topic-heat {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: .78rem;
  font-weight: 700;
  color: #ea580c;
  background: #ffedd5;
  padding: 3px 9px;
  border-radius: 999px;
}

/* ------------------------------ 关于作者 ------------------------------ */
.author-panel {
  display: grid;
  grid-template-columns: 300px 1fr;
  gap: 56px;
  align-items: start;
  background: linear-gradient(180deg, var(--bg-soft), #fff 70%);
  border: 1px solid var(--line);
  border-radius: 24px;
  padding: clamp(32px, 5vw, 56px);
}

.author-avatar-wrap { display: grid; justify-items: center; gap: 18px; }
.author-avatar {
  width: 168px; height: 168px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  font-size: 4rem;
  font-weight: 800;
  color: #fff;
  background: linear-gradient(135deg, var(--blue) 0%, var(--cyan) 120%);
  box-shadow: var(--shadow-lg), 0 0 0 8px #fff, 0 0 0 10px var(--blue-soft);
}
.author-badge {
  font-size: .84rem;
  font-weight: 700;
  color: var(--gray);
  background: #fff;
  border: 1px solid var(--line);
  padding: 8px 16px;
  border-radius: 999px;
  box-shadow: var(--shadow-sm);
}

.author-info .section-title { margin-bottom: 16px; }
.author-bio { color: var(--gray); margin-bottom: 22px; }

.author-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 28px; }
.author-tags li {
  font-size: .82rem;
  font-weight: 600;
  font-family: var(--font-mono);
  color: var(--blue-dark);
  background: var(--blue-tint);
  border: 1px solid var(--blue-soft);
  padding: 5px 14px;
  border-radius: 8px;
}

.author-stats {
  display: flex;
  gap: clamp(28px, 5vw, 56px);
  margin-bottom: 30px;
}
.author-stats dt { font-size: 1.5rem; font-weight: 800; color: var(--ink); letter-spacing: -.01em; }
.author-stats dd { font-size: .84rem; color: var(--muted); }

.author-social { display: flex; gap: 12px; }
.author-social a {
  width: 42px; height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  color: var(--gray);
  background: #fff;
  border: 1px solid var(--line);
  transition: all .25s var(--ease);
}
.author-social a:hover {
  color: #fff;
  background: var(--blue);
  border-color: var(--blue);
  transform: translateY(-3px);
  box-shadow: 0 8px 18px -6px rgba(37, 99, 235, .55);
}

/* ------------------------------ 订阅新闻通讯 ------------------------------ */
.newsletter-panel {
  position: relative;
  overflow: hidden;
  border-radius: 28px;
  background:
    radial-gradient(700px 300px at 90% -20%, rgba(56, 189, 248, .25), transparent 60%),
    linear-gradient(135deg, var(--blue-deep) 0%, #1e3a8a 55%, #1d4ed8 120%);
  color: #fff;
  padding: clamp(44px, 6vw, 72px);
  box-shadow: 0 30px 60px -24px rgba(23, 37, 84, .55);
}

.newsletter-grid-dots {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, .14) 1px, transparent 1.4px);
  background-size: 26px 26px;
  mask-image: radial-gradient(600px 400px at 80% 0%, rgba(0,0,0,.8), transparent 75%);
  -webkit-mask-image: radial-gradient(600px 400px at 80% 0%, rgba(0,0,0,.8), transparent 75%);
  pointer-events: none;
}
.newsletter-glow {
  position: absolute;
  width: 420px; height: 420px;
  left: -120px; bottom: -180px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(56, 189, 248, .3), transparent 65%);
  filter: blur(40px);
  pointer-events: none;
  animation: drift 18s ease-in-out infinite alternate;
}

.newsletter-content { position: relative; z-index: 1; max-width: 620px; }
.newsletter-eyebrow {
  font-size: .78rem;
  font-weight: 700;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: #93c5fd;
  margin-bottom: 12px;
}
.newsletter-title {
  font-size: clamp(1.7rem, 3.6vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -.01em;
  margin-bottom: 14px;
}
.newsletter-desc { color: rgba(255, 255, 255, .78); margin-bottom: 32px; }

.newsletter-form {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.input-wrap {
  position: relative;
  flex: 1 1 300px;
}
.input-icon {
  position: absolute;
  left: 18px; top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  pointer-events: none;
}
.newsletter-form input {
  width: 100%;
  height: 54px;
  padding: 0 18px 0 46px;
  border-radius: 999px;
  border: 1.5px solid transparent;
  background: rgba(255, 255, 255, .97);
  color: var(--ink);
  font: inherit;
  font-size: .98rem;
  outline: none;
  transition: border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.newsletter-form input::placeholder { color: var(--muted); }
.newsletter-form input:focus {
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(14, 165, 233, .3);
}
.newsletter-form.error input {
  border-color: #f87171;
  box-shadow: 0 0 0 4px rgba(248, 113, 113, .25);
  animation: shake .4s var(--ease);
}
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}

.newsletter-msg {
  min-height: 26px;
  margin-top: 14px;
  font-size: .92rem;
  font-weight: 600;
}
.newsletter-msg.err { color: #fca5a5; }
.newsletter-msg.ok { color: #86efac; }

.newsletter-note {
  font-size: .84rem;
  color: rgba(255, 255, 255, .6);
}
.newsletter-note strong { color: #fff; font-weight: 700; }

/* ------------------------------ 页脚 ------------------------------ */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.2fr;
  gap: 40px;
  padding: 64px 24px 48px;
}
.footer-brand p {
  color: var(--gray);
  font-size: .92rem;
  margin-top: 16px;
  max-width: 300px;
}
.footer-col h3 {
  font-size: .82rem;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 16px;
}
.footer-col a {
  display: block;
  color: var(--gray);
  font-size: .92rem;
  padding: 5px 0;
  transition: color .2s var(--ease), transform .2s var(--ease);
}
.footer-col a:hover { color: var(--blue); transform: translateX(3px); }

.footer-social { display: flex; gap: 10px; margin-bottom: 18px; }
.footer-social a {
  width: 38px; height: 38px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  color: var(--gray);
  background: #fff;
  border: 1px solid var(--line);
  transition: all .25s var(--ease);
}
.footer-social a:hover { color: #fff; background: var(--blue); border-color: var(--blue); transform: translateY(-2px); }
.footer-note { font-size: .86rem; color: var(--muted); }
.footer-note a { display: inline; color: var(--blue); }

.footer-bottom { border-top: 1px solid var(--line); }
.footer-bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  padding-top: 22px;
  padding-bottom: 22px;
  font-size: .84rem;
  color: var(--muted);
}

/* ------------------------------ 回到顶部 ------------------------------ */
.back-to-top {
  position: fixed;
  right: 26px; bottom: 26px;
  width: 46px; height: 46px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--blue);
  color: #fff;
  box-shadow: 0 10px 24px -8px rgba(37, 99, 235, .6);
  opacity: 0;
  visibility: hidden;
  transform: translateY(14px);
  transition: all .3s var(--ease);
  z-index: 90;
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--blue-dark); transform: translateY(-3px); }

/* ------------------------------ 进场动画 ------------------------------ */
.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .7s var(--ease), transform .7s var(--ease);
  transition-delay: var(--d, 0s);
}
.reveal.in-view { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* ------------------------------ 响应式 ------------------------------ */
@media (max-width: 1024px) {
  .featured-grid { grid-template-columns: 1fr; }
  .featured-side { grid-template-rows: none; grid-template-columns: 1fr 1fr; }
  .article-grid { grid-template-columns: repeat(2, 1fr); }
  .category-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .author-panel { grid-template-columns: 1fr; gap: 36px; }
  .author-avatar-wrap { justify-items: start; }
}

@media (max-width: 768px) {
  .section { padding: 72px 0; }

  .menu-toggle { display: flex; }

  .main-nav {
    position: fixed;
    top: var(--header-h);
    left: 0; right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 16px 24px 24px;
    background: rgba(255, 255, 255, .98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 40px -20px rgba(15, 23, 42, .2);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform .3s var(--ease), opacity .3s var(--ease), visibility .3s;
  }
  .main-nav.open { transform: translateY(0); opacity: 1; visibility: visible; }
  .nav-link { padding: 12px 10px; font-size: 1rem; }
  .nav-link::after { display: none; }
  .nav-cta { margin: 12px 0 0; justify-content: center; }

  .hero { min-height: auto; padding-bottom: 96px; }
  .hero-stats { max-width: none; }

  .featured-side { grid-template-columns: 1fr; }
  .article-grid { grid-template-columns: 1fr; }
  .category-grid { grid-template-columns: 1fr 1fr; gap: 14px; }
  .category-card { padding: 20px 18px 18px; }
  .section-head { margin-bottom: 36px; }

  .newsletter-form .btn-light { width: 100%; justify-content: center; }

  .back-to-top { right: 18px; bottom: 18px; }
}

@media (max-width: 520px) {
  .category-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; padding-top: 48px; }
  .hero-actions .btn { flex: 1; justify-content: center; }
  .author-stats { flex-wrap: wrap; gap: 22px; }
  .scroll-hint { display: none; }
}