/* ============================================================
   7ART · 漆艺笔记
   Apple-inspired UI design system (apple-ui-design skill)
   Accent: 大漆朱红  #c43d2b
   ============================================================ */

:root {
  /* Typography hierarchy (SF Pro style) */
  --text-hero: 600 48px/1.1;
  --text-title: 600 32px/1.2;
  --text-body: 400 17px/1.5;
  --text-caption: 400 13px/1.4;

  /* Spacing rhythm 4/8/16/24/48/96 */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 48px;
  --space-2xl: 96px;

  /* Light mode */
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f7;
  --text-primary: #1d1d1f;
  --text-secondary: #86868b;
  --accent: #c43d2b;
  --accent-strong: #a83221;
  --accent-soft: rgba(196, 61, 43, 0.09);
  --border: rgba(0, 0, 0, 0.06);
  --card-bg: rgba(255, 255, 255, 0.8);
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
  --nav-bg: rgba(255, 255, 255, 0.72);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #000000;
    --bg-secondary: #1d1d1f;
    --text-primary: #f5f5f7;
    --text-secondary: #a1a1a6;
    --accent: #e5533d;
    --accent-strong: #f0654f;
    --accent-soft: rgba(229, 83, 61, 0.14);
    --border: rgba(255, 255, 255, 0.1);
    --card-bg: rgba(29, 29, 31, 0.72);
    --shadow: 0 4px 24px rgba(0, 0, 0, 0.45);
    --nav-bg: rgba(0, 0, 0, 0.72);
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font: var(--text-body);
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  transition: background 0.3s cubic-bezier(0.25, 0.1, 0.25, 1), color 0.3s ease;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.2s ease;
}
a:hover {
  opacity: 0.8;
}

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

/* ---------- Navigation (frosted glass) ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 56px;
  flex-wrap: wrap;
}
.brand {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: 0.5px;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) 0;
}
.brand-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  display: inline-block;
}
.nav-links {
  display: flex;
  list-style: none;
  gap: var(--space-lg);
  flex-wrap: wrap;
  padding: var(--space-sm) 0;
}
.nav-links a {
  font-size: 15px;
  color: var(--text-secondary);
  padding: var(--space-sm) var(--space-xs);
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  font-weight: 500;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
}
.nav-links a.active {
  color: var(--accent);
}

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  text-align: center;
  padding: var(--space-2xl) var(--space-lg) var(--space-xl);
  animation: fadeUp 0.6s cubic-bezier(0.25, 0.1, 0.25, 1) both;
}
.hero-kicker {
  font-size: 15px;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 3px;
  text-transform: uppercase;
  margin-bottom: var(--space-md);
}
.hero h1 {
  font: var(--text-hero);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-md);
}
.hero p {
  font-size: 21px;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto var(--space-xl);
}
.hero-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 12px 28px;
  border-radius: 980px;
  font-size: 17px;
  font-weight: 500;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}
.btn-primary {
  background: var(--accent);
  color: #ffffff;
}
.btn-primary:hover {
  transform: scale(1.02);
  filter: brightness(1.1);
  opacity: 1;
}
.btn-secondary {
  background: var(--accent-soft);
  color: var(--accent);
}
.btn-secondary:hover {
  transform: scale(1.02);
  opacity: 1;
}

/* ---------- Layout ---------- */
.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}
.section {
  padding: var(--space-2xl) 0;
}
.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
  flex-wrap: wrap;
  gap: var(--space-sm);
}
.section-head h2 {
  font: var(--text-title);
  letter-spacing: -0.015em;
}
.section-head .more {
  font-size: 15px;
  color: var(--text-secondary);
}

/* ---------- Cards (frosted glass) ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-lg);
}
.card {
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-radius: 18px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  transition: transform 0.3s cubic-bezier(0.25, 0.1, 0.25, 1), box-shadow 0.3s ease;
}
a.card {
  color: var(--text-primary);
}
a.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  opacity: 1;
}
.card .card-title {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.01em;
}
.card .card-cat {
  font: var(--text-caption);
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 1px;
}
.card .card-date {
  font: var(--text-caption);
  color: var(--text-secondary);
}
.card .card-desc {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.5;
}
.card .card-img {
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: var(--space-xs);
  background: var(--bg-secondary);
  aspect-ratio: 16 / 9;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font: var(--text-caption);
}
.card .card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.post-cover {
  margin-bottom: var(--space-lg);
}

/* 栏目导航卡片（首页用） */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-md);
}
.cat-card {
  border-radius: 18px;
  border: 1px solid var(--border);
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  padding: var(--space-lg);
  display: block;
  color: var(--text-primary);
  transition: transform 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
}
.cat-card:hover {
  transform: translateY(-3px);
  opacity: 1;
}
.cat-badge {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 18px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-sm);
}
.cat-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}
.cat-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ---------- Page header ---------- */
.page-head {
  text-align: center;
  padding: var(--space-xl) var(--space-lg) var(--space-lg);
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
}
.page-head h1 {
  font: var(--text-title);
  letter-spacing: -0.015em;
}
.page-head p {
  color: var(--text-secondary);
  max-width: 640px;
  margin: var(--space-sm) auto 0;
  font-size: 16px;
}

/* ---------- Article / post ---------- */
.post {
  max-width: 680px;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
}
.post h1 {
  font: var(--text-title);
  letter-spacing: -0.015em;
  margin-bottom: var(--space-sm);
}
.post-meta {
  font: var(--text-caption);
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
}
.post-body {
  font-size: 17px;
  line-height: 1.75;
  color: var(--text-primary);
}
.post-body h2 {
  font-size: 24px;
  font-weight: 600;
  margin: var(--space-xl) 0 var(--space-md);
  letter-spacing: -0.01em;
}
.post-body h3 {
  font-size: 19px;
  font-weight: 600;
  margin: var(--space-lg) 0 var(--space-sm);
}
.post-body p {
  margin-bottom: var(--space-md);
}
.post-body ul,
.post-body ol {
  margin: 0 0 var(--space-md) var(--space-lg);
}
.post-body li {
  margin-bottom: var(--space-xs);
}
.post-body blockquote {
  border-left: 3px solid var(--accent);
  padding: var(--space-sm) var(--space-md);
  margin: var(--space-md) 0;
  color: var(--text-secondary);
  background: var(--accent-soft);
  border-radius: 0 10px 10px 0;
}
.post-body code {
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: 0.9em;
}
.post-body a {
  text-decoration: underline;
  text-underline-offset: 3px;
}
.post-note {
  margin-top: var(--space-xl);
  padding: var(--space-md);
  background: var(--accent-soft);
  border-radius: 12px;
  font-size: 14px;
  color: var(--text-secondary);
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  padding: var(--space-xl) var(--space-lg);
  text-align: center;
  color: var(--text-secondary);
  font: var(--text-caption);
  background: var(--bg-secondary);
}
.footer .brand {
  justify-content: center;
  font-size: 15px;
  color: var(--text-secondary);
}
.footer a {
  color: var(--text-secondary);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- Animations ---------- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  :root {
    --text-hero: 600 34px/1.15;
    --text-title: 600 26px/1.2;
  }
  .nav-inner {
    padding: 0 var(--space-md);
  }
  .nav-links {
    gap: var(--space-sm);
    width: 100%;
    overflow-x: auto;
  }
  .hero p {
    font-size: 18px;
  }
  .section {
    padding: var(--space-xl) 0;
  }
  .btn {
    padding: 12px 22px;
    font-size: 16px;
  }
}

/* 无障碍：触控目标、对比度 */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation: none !important; transition: none !important; }
}