/* 上海讲座 - 全站样式 v2 */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@400;500;700;900&family=Noto+Serif+SC:wght@600;700;900&display=swap');

:root {
  --bg: #f5f7fb;
  --bg-grad: linear-gradient(180deg, #f6f8fc 0%, #eef2fb 100%);
  --surface: #ffffff;
  --primary: #1e3a8a;
  --primary-dark: #152c66;
  --primary-darker: #0f2050;
  --primary-soft: #eef2fb;
  --primary-mid: #3b5db8;
  --accent: #c79a3a;
  --accent-soft: #fcf5e6;
  --text: #1f2937;
  --text-light: #4b5563;
  --muted: #6b7280;
  --muted-2: #9ca3af;
  --border: #e5e8ef;
  --border-strong: #d1d5db;
  --danger: #c0392b;
  --ok: #1f9d55;
  --warn: #d97706;
  --radius: 14px;
  --radius-lg: 22px;
  --shadow: 0 8px 28px rgba(20, 40, 90, 0.08);
  --shadow-md: 0 4px 14px rgba(20, 40, 90, 0.06);
  --shadow-sm: 0 2px 8px rgba(20, 40, 90, 0.06);
  --maxw: 1120px;
  --font: "Noto Sans SC", system-ui, -apple-system, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: "Noto Serif SC", Georgia, serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg-grad);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  min-height: 100vh;
  display: flex; flex-direction: column;
}
main { flex: 1; }
a { color: inherit; text-decoration: none; transition: color .18s; }
img { max-width: 100%; display: block; }
.hidden { display: none !important; }
.muted { color: var(--muted); font-weight: 400; }
.hint { color: var(--muted); font-size: 13px; margin: 6px 0; }
.hint.center { text-align: center; }
code { background: var(--primary-soft); padding: 1px 6px; border-radius: 5px; font-size: 13px; color: var(--primary); }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 10px 18px; border-radius: 10px; border: 1px solid transparent;
  font-size: 14px; font-weight: 500; cursor: pointer; transition: .2s; font-family: var(--font);
  white-space: nowrap;
}
.btn-sm { padding: 7px 14px; font-size: 13px; border-radius: 8px; }
.btn-primary { background: var(--primary); color: #fff; box-shadow: 0 2px 6px rgba(30,58,138,.25); }
.btn-primary:hover { background: var(--primary-dark); box-shadow: 0 4px 12px rgba(30,58,138,.32); transform: translateY(-1px); }
.btn-ghost { background: transparent; border-color: var(--border-strong); color: var(--text); }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-soft); }
.btn-danger { background: #fff; border-color: var(--danger); color: var(--danger); }
.btn-danger:hover { background: var(--danger); color: #fff; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255,255,255,.92); backdrop-filter: saturate(1.5) blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; gap: 12px; }
.brand {
  display: flex; align-items: center; gap: 12px; font-weight: 700;
  flex: 0 0 auto;
}
.brand-logo {
  width: 44px; height: 44px; border-radius: 10px;
  object-fit: cover;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}
.brand-text { display: flex; flex-direction: column; line-height: 1.15; font-size: 18px; color: var(--text); }
.brand-sub { font-size: 11px; color: var(--muted); font-weight: 500; letter-spacing: .4px; margin-top: 2px; }
.nav-links {
  display: flex; align-items: center; gap: 26px;
}
.nav-links > a { color: var(--text-light); font-weight: 500; font-size: 15px; position: relative; padding: 6px 0; }
.nav-links > a:hover { color: var(--primary); }
.nav-links > a:hover::after {
  content: ''; position: absolute; left: 0; right: 0; bottom: 0; height: 2px;
  background: var(--primary); border-radius: 2px;
}
.nav-auth, .nav-user { display: flex; align-items: center; gap: 8px; }
.nav-user-name { font-size: 14px; color: var(--text-light); margin-right: 6px; }
.nav-toggle {
  display: none; background: none; border: none; font-size: 24px;
  cursor: pointer; color: var(--text); padding: 6px;
}

/* ---------- Hero (Homepage) ---------- */
.hero {
  background:
    radial-gradient(80% 60% at 20% 0%, rgba(255,255,255,0.16), transparent 60%),
    radial-gradient(60% 50% at 100% 100%, rgba(199,154,58,0.18), transparent 50%),
    linear-gradient(135deg, #152c66 0%, #1e3a8a 45%, #2b4ea8 100%);
  color: #fff; padding: 80px 0 90px;
  position: relative; overflow: hidden;
  text-align: center;
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 60 60'><circle cx='1' cy='1' r='1' fill='%23ffffff' opacity='0.08'/></svg>");
  background-size: 24px 24px;
  pointer-events: none;
}
.hero h1 {
  font-family: var(--serif);
  font-size: clamp(28px, 5vw, 48px);
  font-weight: 900; margin: 0 0 16px;
  letter-spacing: 0.5px;
  text-shadow: 0 2px 12px rgba(0,0,0,.18);
}
.hero-sub {
  font-size: clamp(15px, 2vw, 18px);
  color: rgba(255,255,255,.86);
  max-width: 720px; margin: 0 auto 32px;
}
.hero .brand-logo { display: none; }

.hero-search {
  display: flex; gap: 8px; max-width: 560px; margin: 0 auto;
  background: rgba(255,255,255,.95); padding: 6px;
  border-radius: 14px; box-shadow: 0 16px 40px rgba(0,0,0,.18);
}
.hero-search input {
  flex: 1; border: none; outline: none; padding: 12px 16px;
  border-radius: 10px; font-size: 15px; background: transparent;
  font-family: var(--font);
}
.hero-search .btn { padding: 12px 24px; font-weight: 600; }

.hero-stats {
  display: flex; justify-content: center; gap: 36px;
  margin-top: 36px; flex-wrap: wrap;
}
.hero-stat strong { display: block; font-size: 24px; font-weight: 700; }
.hero-stat span { font-size: 13px; color: rgba(255,255,255,.72); letter-spacing: 1px; }

/* ---------- Sub-hero (about/non-home) ---------- */
.sub-hero {
  background:
    radial-gradient(60% 60% at 50% 0%, rgba(255,255,255,0.6), transparent 70%),
    linear-gradient(135deg, #1e3a8a 0%, #2b4ea8 60%, #355fb8 100%);
  color: #fff; padding: 64px 0 56px;
  text-align: center;
}
.sub-hero h1 {
  font-family: var(--serif);
  font-size: clamp(26px, 4.5vw, 42px);
  font-weight: 900; margin: 0 0 12px;
  text-shadow: 0 2px 12px rgba(0,0,0,.18);
}
.sub-hero-sub { color: rgba(255,255,255,.85); font-size: 17px; }

/* ---------- Main & common page ---------- */
.main { padding: 36px 0 60px; }
.panel {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow-sm);
  margin-bottom: 20px;
}
.panel h3 { margin: 0 0 14px; font-size: 17px; color: var(--text); }

/* ---------- Filter chips ---------- */
.filter-bar {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow-sm);
  margin-bottom: 20px;
}
.chip-group { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }
.chip-group:last-child { margin-bottom: 0; }
.chip {
  padding: 7px 14px; border-radius: 999px; border: 1px solid var(--border-strong);
  background: #fff; cursor: pointer; font-size: 13px; color: var(--text-light);
  transition: .15s; font-family: var(--font);
}
.chip:hover { border-color: var(--primary); color: var(--primary); }
.chip.active { background: var(--primary); color: #fff; border-color: var(--primary); }
#location {
  width: 100%; padding: 9px 14px; border-radius: 10px;
  border: 1px solid var(--border-strong); outline: none;
  font-size: 14px; font-family: var(--font); transition: border-color .15s;
}
#location:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(30,58,138,.1); }

/* ---------- Lecture cards grid ---------- */
.grid-cards {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 18px;
}
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden;
  transition: transform .22s, box-shadow .22s, border-color .22s;
  display: flex; flex-direction: column;
}
.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
  border-color: var(--primary-soft);
}
.card-poster {
  position: relative; aspect-ratio: 16 / 10;
  background: linear-gradient(135deg, #2b4ea8, #152c66);
  display: grid; place-items: center; overflow: hidden;
}
.card-poster img { width: 100%; height: 100%; object-fit: cover; }
.poster-ph {
  font-family: var(--serif); font-size: 60px; color: rgba(255,255,255,.4);
  font-weight: 900;
}
.badge {
  position: absolute; top: 10px; left: 10px;
  font-size: 12px; padding: 4px 10px; border-radius: 999px;
  background: rgba(15,32,80,.78); color: #fff; font-weight: 500;
  backdrop-filter: blur(6px);
}
.badge-academic { background: rgba(99,102,241,.92); }
.badge-art { background: rgba(236,72,153,.88); }
.badge-tech { background: rgba(14,165,233,.9); }
.badge-biz { background: rgba(245,158,11,.92); }
.badge-culture { background: rgba(16,185,129,.92); }
.badge-other { background: rgba(107,114,128,.92); }
.card-body { padding: 14px 16px 16px; flex: 1; display: flex; flex-direction: column; }
.card-title { font-size: 16px; font-weight: 700; margin: 0 0 8px; line-height: 1.4; color: var(--text); }
.card-meta { font-size: 13px; color: var(--muted); margin-top: 4px; display: flex; align-items: center; gap: 4px; }

/* ---------- Empty / loading / error ---------- */
.empty, .loading, .error {
  background: var(--surface); border: 1px dashed var(--border-strong);
  border-radius: var(--radius);
  padding: 48px 20px; text-align: center; color: var(--muted); margin: 12px 0;
}
.error { border-color: rgba(192,57,43,.4); background: #fff5f5; color: var(--danger); }
.loading::before {
  content: ''; display: inline-block; width: 16px; height: 16px;
  border: 2px solid var(--primary-soft); border-top-color: var(--primary);
  border-radius: 50%; animation: spin .8s linear infinite; margin-right: 8px;
  vertical-align: -2px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- Detail page ---------- */
.detail { display: grid; grid-template-columns: 1.7fr 1fr; gap: 24px; align-items: start; }
.detail-main {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-sm);
}
.detail-poster {
  aspect-ratio: 16/9; background: linear-gradient(135deg, #2b4ea8, #152c66);
  display: grid; place-items: center; position: relative; overflow: hidden;
}
.detail-poster img { width: 100%; height: 100%; object-fit: cover; }
.detail-poster-ph {
  font-family: var(--serif); font-size: 120px; color: rgba(255,255,255,.4); font-weight: 900;
}
.detail-badge { top: 16px; left: 16px; font-size: 14px; padding: 6px 14px; }
.detail-info { padding: 24px 28px 28px; }
.detail-info h1 { font-family: var(--serif); font-size: 26px; margin: 0 0 16px; line-height: 1.35; }
.meta-list { list-style: none; padding: 0; margin: 0 0 18px; display: grid; gap: 8px; }
.meta-list li { font-size: 14px; color: var(--text-light); display: grid; grid-template-columns: 70px 1fr; gap: 12px; }
.meta-list li span { color: var(--muted); font-size: 13px; }
.detail-desc {
  white-space: pre-wrap; line-height: 1.8; color: var(--text-light);
  background: var(--bg); padding: 16px 18px; border-radius: 12px;
  border-left: 3px solid var(--primary); margin: 18px 0;
}
.detail-actions { display: flex; gap: 10px; flex-wrap: wrap; }

.detail-side { position: sticky; top: 90px; }
.qr-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 22px;
  text-align: center; box-shadow: var(--shadow-sm);
}
.qr-card h3 { margin: 0 0 14px; font-size: 17px; }
.qr-card img { width: 100%; max-width: 240px; margin: 0 auto; border-radius: 12px; border: 1px solid var(--border); }
.qr-tip { font-size: 13px; color: var(--muted); margin: 12px 0 0; }
.qr-empty { color: var(--muted); padding: 20px 0; font-size: 14px; }
.back-link { display: inline-block; margin-bottom: 18px; color: var(--primary); font-size: 14px; }
.back-link:hover { text-decoration: underline; }

/* ---------- Auth (login / register) ---------- */
.auth-wrap { padding: 60px 20px; }
.auth-card {
  max-width: 460px; margin: 0 auto; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  box-shadow: var(--shadow); padding: 28px;
}
.tabs { display: flex; border-bottom: 1px solid var(--border); margin-bottom: 24px; }
.tab {
  background: none; border: none; padding: 12px 18px;
  font-size: 15px; color: var(--muted); cursor: pointer;
  font-family: var(--font); font-weight: 500;
  border-bottom: 2px solid transparent; margin-bottom: -1px;
}
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }
.auth-form h2 { font-family: var(--serif); font-size: 24px; margin: 0 0 16px; }
.auth-form label { display: block; margin: 12px 0; font-size: 14px; color: var(--text-light); font-weight: 500; }
.auth-form input, .auth-form textarea, .auth-form select {
  display: block; width: 100%; padding: 10px 14px; margin-top: 6px;
  border: 1px solid var(--border-strong); border-radius: 10px;
  font-size: 14px; font-family: var(--font); outline: none;
  transition: border-color .15s, box-shadow .15s;
}
.auth-form input:focus, .auth-form textarea:focus, .auth-form select:focus {
  border-color: var(--primary); box-shadow: 0 0 0 3px rgba(30,58,138,.1);
}
.checkbox-row { display: flex; align-items: center; gap: 8px; margin: 14px 0; font-size: 14px; color: var(--text-light); cursor: pointer; }
.checkbox-row input { width: auto; margin: 0; }
.auth-form .btn { width: 100%; padding: 12px; font-size: 15px; margin-top: 12px; }
.auth-form .msg { min-height: 18px; margin-top: 10px; font-size: 13px; text-align: center; }
.auth-form .msg.error { color: var(--danger); }
.auth-form .msg.ok { color: var(--ok); }

/* ---------- Form grid (dashboard) ---------- */
.form-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px 18px;
}
.form-grid label { display: block; font-size: 13px; color: var(--text-light); font-weight: 500; }
.form-grid label > input, .form-grid label > textarea, .form-grid label > select {
  display: block; width: 100%; padding: 9px 12px; margin-top: 6px;
  border: 1px solid var(--border-strong); border-radius: 8px;
  font-size: 14px; font-family: var(--font); outline: none;
}
.form-grid label.full { grid-column: 1 / -1; }
.form-grid label > textarea { min-height: 100px; resize: vertical; }
.form-actions { margin-top: 18px; display: flex; gap: 10px; }

/* ---------- Admin / list tables ---------- */
.admin-actions { margin: 0 0 20px; display: flex; gap: 10px; flex-wrap: wrap; }
.list-table { width: 100%; border-collapse: collapse; }
.list-table th, .list-table td {
  padding: 12px 14px; border-bottom: 1px solid var(--border);
  text-align: left; font-size: 14px;
}
.list-table th { font-weight: 600; color: var(--text-light); background: var(--bg); font-size: 13px; }
.list-table tr:hover td { background: var(--primary-soft); }
.status-pending { color: var(--warn); font-weight: 600; }
.status-approved { color: var(--ok); font-weight: 600; }
.status-rejected { color: var(--danger); font-weight: 600; }
.row-actions { display: flex; gap: 6px; }

.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: rgba(15,32,80,.92); color: #fff; padding: 12px 22px;
  border-radius: 999px; font-size: 14px; box-shadow: 0 8px 32px rgba(0,0,0,.3);
  z-index: 100; opacity: 0; pointer-events: none; transition: opacity .25s;
}
.toast.show { opacity: 1; }

/* ---------- About page specific ---------- */
.about-page .main { padding: 32px 0 60px; }
.about-main { max-width: 920px; }
.intro-card {
  display: grid; grid-template-columns: 1.5fr 1fr;
  gap: 32px; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius-lg);
  padding: 32px; box-shadow: var(--shadow);
  margin-top: -48px; position: relative; z-index: 2;
}
.intro-text .lead { font-size: 16px; line-height: 1.85; color: var(--text-light); margin: 0 0 14px; }
.intro-text .lead strong { color: var(--primary); }
.intro-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.pill {
  display: inline-block; padding: 5px 12px; border-radius: 999px;
  background: var(--primary-soft); color: var(--primary-dark);
  font-size: 13px; font-weight: 500;
}
.intro-side { display: grid; place-items: center; }
.qr-block {
  text-align: center;
  background: var(--bg); border-radius: 16px;
  padding: 22px 18px 16px; border: 1px solid var(--border);
}
.qr-block .qr-img {
  width: 100%; max-width: 200px; aspect-ratio: 1/1;
  object-fit: contain;
  border-radius: 12px; background: #fff; border: 1px solid var(--border);
}
.qr-block p { font-size: 14px; color: var(--text-light); margin: 12px 0 4px; font-weight: 500; }

.section-block {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 36px;
  margin-top: 24px; box-shadow: var(--shadow-sm);
}
.section-block h2 {
  font-family: var(--serif); font-size: 26px; margin: 0 0 8px; color: var(--text);
  position: relative; padding-bottom: 14px;
}
.section-block h2::after {
  content: ''; display: block; width: 48px; height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px; margin-top: 12px;
}
.lead-muted { font-size: 15px; color: var(--muted); margin: 8px 0 0; }

.grid { display: grid; gap: 18px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.mt-24 { margin-top: 24px; }
.center { text-align: center; }

.feature-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 22px;
  transition: transform .2s, box-shadow .2s;
}
.feature-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--primary-soft); }
.fc-icon { font-size: 32px; margin-bottom: 12px; }
.feature-card h4 { font-family: var(--serif); font-size: 18px; margin: 0 0 8px; color: var(--primary-dark); }
.feature-card p { margin: 0; font-size: 14px; color: var(--text-light); line-height: 1.7; }

.role-card {
  border-radius: var(--radius-lg); padding: 28px;
  border: 1px solid var(--border); background: var(--surface);
  position: relative; overflow: hidden;
}
.role-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
}
.role-listen { background: linear-gradient(160deg, #ffffff 70%, #f0f4ff 100%); }
.role-organize { background: linear-gradient(160deg, #ffffff 70%, #fcf5e6 100%); }
.role-card h3 {
  font-family: var(--serif); font-size: 20px; margin: 6px 0 14px;
  color: var(--primary-dark); display: flex; align-items: center; gap: 8px;
}
.role-card ul { padding-left: 18px; margin: 0; }
.role-card li { font-size: 14px; color: var(--text-light); margin: 8px 0; line-height: 1.7; }
.role-card li strong { color: var(--primary); }

.steps {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  counter-reset: step;
}
.step {
  background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px 18px; position: relative;
}
.step-num {
  width: 36px; height: 36px; border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-mid));
  color: #fff; font-weight: 700; font-size: 16px;
  display: grid; place-items: center;
  margin-bottom: 12px;
  box-shadow: 0 4px 12px rgba(30,58,138,.25);
}
.step h4 { margin: 0 0 6px; font-size: 15px; color: var(--text); }
.step p { font-size: 13px; margin: 0; line-height: 1.65; }

.qr-big { text-align: center; }
.qr-big h2 { text-align: left; }
.qr-big-frame {
  display: inline-block;
  background: #fff; border: 1px solid var(--border);
  padding: 20px; border-radius: 16px;
  margin: 18px auto;
  box-shadow: var(--shadow);
}
.qr-big-frame img { width: 220px; height: 220px; object-fit: contain; border-radius: 8px; }

/* ---------- Footer ---------- */
.site-footer {
  background: var(--primary-darker);
  background: linear-gradient(180deg, #0f2050 0%, #091436 100%);
  color: rgba(255,255,255,.78);
  padding: 48px 0 24px; margin-top: 60px;
}
.footer-grid {
  display: grid; grid-template-columns: 1.4fr 1fr 1fr 1.1fr; gap: 36px;
}
.footer-brand p { margin: 8px 0 0; font-size: 13px; line-height: 1.7; }
.brand-footer { display: flex; align-items: center; gap: 12px; }
.brand-footer strong { color: #fff; font-size: 17px; }
.brand-footer .muted { color: rgba(255,255,255,.55); font-size: 12px; }
.footer-logo {
  width: 44px; height: 44px; border-radius: 10px;
  object-fit: cover; border: 1px solid rgba(255,255,255,.2);
}
.site-footer h4 {
  color: #fff; font-size: 14px; margin: 0 0 14px;
  letter-spacing: .5px; text-transform: uppercase;
}
.site-footer a { display: block; padding: 4px 0; color: rgba(255,255,255,.78); font-size: 14px; }
.site-footer a:hover { color: #fff; }
.footer-qr-card { text-align: center; }
.footer-qr-card .qr-frame {
  background: #fff; border-radius: 12px; padding: 8px;
  display: inline-block; margin: 0 auto 10px;
}
.footer-qr-card .qr-frame img {
  width: 130px; height: 130px; object-fit: contain; border-radius: 6px;
  display: block;
}
.footer-qr-card .hint { color: rgba(255,255,255,.6); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.12);
  margin-top: 28px; padding-top: 18px;
  font-size: 13px; color: rgba(255,255,255,.55); text-align: center;
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .nav-links { gap: 16px; }
  .detail, .intro-card { grid-template-columns: 1fr; }
  .detail-side { position: static; }
  .steps { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .form-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .nav { height: 60px; }
  .brand-text { font-size: 15px; }
  .brand-sub { display: none; }
  .nav-links > a:not(.btn) { display: none; }
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute; top: 60px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--border);
    flex-direction: column; align-items: stretch;
    padding: 12px 16px 16px; gap: 10px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links > a:not(.btn) { display: block; padding: 10px 0; }
  .nav-auth, .nav-user { flex-wrap: wrap; }
  .hero { padding: 56px 0 64px; }
  .hero-search { flex-direction: column; }
  .sub-hero { padding: 48px 0 40px; }
  .grid-2, .grid-3, .steps { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; text-align: center; }
  .brand-footer, .footer-qr-card { justify-content: center; }
  .section-block { padding: 24px 20px; }
  .intro-card { grid-template-columns: 1fr; padding: 22px; margin-top: -28px; }
  .card-title { font-size: 15px; }
}