/* ─── Reset & Base ─────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #eef2ff;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --success: #10b981;
  --text: #111827;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --bg: #f9fafb;
  --card-bg: #ffffff;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.08), 0 4px 6px rgba(0,0,0,0.05);
}

html { font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: var(--text);
  background: var(--bg);
  min-height: 100vh;
  line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ─── Layout ───────────────────────────────────────────────────────────────── */
.container { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.container-sm { max-width: 780px; margin: 0 auto; padding: 0 24px; }

/* ─── Header ───────────────────────────────────────────────────────────────── */
.site-header {
  background: var(--card-bg);
  border-bottom: 1px solid var(--border);
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}
.site-header .inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.site-logo {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}
.site-logo:hover { text-decoration: none; opacity: 0.85; }
.header-nav { display: flex; align-items: center; gap: 16px; }
.header-nav a {
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  transition: background 0.15s, color 0.15s;
}
.header-nav a:hover { background: var(--primary-light); color: var(--primary); text-decoration: none; }

/* ─── Buttons ──────────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 18px; border-radius: var(--radius-sm);
  font-size: 0.9rem; font-weight: 500;
  border: none; cursor: pointer;
  transition: background 0.15s, box-shadow 0.15s, transform 0.1s;
  text-decoration: none;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn:active { transform: translateY(0); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); color: #fff; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { background: var(--danger-hover); color: #fff; }
.btn-outline {
  background: transparent; color: var(--primary);
  border: 1.5px solid var(--primary);
}
.btn-outline:hover { background: var(--primary-light); }
.btn-ghost {
  background: transparent; color: var(--text-muted);
  border: 1.5px solid var(--border);
}
.btn-ghost:hover { background: var(--bg); color: var(--text); }
.btn-sm { padding: 5px 12px; font-size: 0.82rem; }

/* ─── Tags ─────────────────────────────────────────────────────────────────── */
.tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 500;
  background: var(--primary-light);
  color: var(--primary);
  cursor: pointer;
  transition: background 0.15s;
}
.tag:hover { background: #dde4ff; }
.tag.active { background: var(--primary); color: #fff; }

/* ─── Forms ────────────────────────────────────────────────────────────────── */
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 0.88rem; font-weight: 600; margin-bottom: 6px; color: var(--text-muted); }
.form-control {
  width: 100%; padding: 10px 14px;
  border: 1.5px solid var(--border); border-radius: var(--radius-sm);
  font-size: 0.95rem; color: var(--text);
  background: var(--card-bg); outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  font-family: inherit;
}
.form-control:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(79,70,229,0.1); }

/* ─── Card ─────────────────────────────────────────────────────────────────── */
.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 24px;
}

/* ─── Toast ────────────────────────────────────────────────────────────────── */
#toast-container {
  position: fixed; bottom: 24px; right: 24px;
  display: flex; flex-direction: column; gap: 8px; z-index: 9999;
}
.toast {
  padding: 12px 20px; border-radius: var(--radius-sm);
  font-size: 0.9rem; color: #fff; font-weight: 500;
  box-shadow: var(--shadow-lg);
  animation: slideIn 0.25s ease;
}
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
.toast.info { background: var(--primary); }
@keyframes slideIn { from { opacity: 0; transform: translateX(40px); } to { opacity: 1; transform: translateX(0); } }

/* ─── Empty / Loading States ───────────────────────────────────────────────── */
.empty-state {
  text-align: center; padding: 80px 20px; color: var(--text-muted);
}
.empty-state .icon { font-size: 3rem; margin-bottom: 12px; }
.empty-state p { font-size: 1rem; }

.loading { text-align: center; padding: 60px; color: var(--text-muted); font-size: 0.95rem; }

/* ─── Prose (note content) ─────────────────────────────────────────────────── */
.prose {
  line-height: 1.8;
  color: var(--text);
  font-size: 1rem;
}
.prose h1, .prose h2, .prose h3, .prose h4 {
  font-weight: 700; line-height: 1.3; margin: 1.5em 0 0.6em;
}
.prose h1 { font-size: 1.8rem; }
.prose h2 { font-size: 1.4rem; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.prose h3 { font-size: 1.15rem; }
.prose p { margin: 0.8em 0; }
.prose ul, .prose ol { margin: 0.8em 0; padding-left: 1.6em; }
.prose li { margin: 0.3em 0; }
.prose blockquote {
  border-left: 4px solid var(--primary);
  background: var(--primary-light);
  margin: 1em 0; padding: 10px 16px;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-muted);
  font-style: italic;
}
.prose code {
  background: #f3f4f6; padding: 2px 6px; border-radius: 4px;
  font-size: 0.88em; font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  color: #d97706;
}
.prose pre {
  background: #1e1e2e; color: #cdd6f4;
  padding: 16px 20px; border-radius: var(--radius-sm);
  overflow-x: auto; margin: 1em 0; line-height: 1.6;
}
.prose pre code {
  background: transparent; padding: 0; color: inherit; font-size: 0.9rem;
}
.prose table { width: 100%; border-collapse: collapse; margin: 1em 0; }
.prose th, .prose td { border: 1px solid var(--border); padding: 8px 14px; text-align: left; }
.prose th { background: var(--bg); font-weight: 600; }
.prose tr:hover td { background: var(--bg); }
.prose img { max-width: 100%; border-radius: var(--radius-sm); }
.prose a { color: var(--primary); }
.prose strong { font-weight: 700; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 1.5em 0; }

/* ─── Responsive ───────────────────────────────────────────────────────────── */
@media (max-width: 640px) {
  .container, .container-sm { padding: 0 16px; }
  .site-header .inner { height: 52px; }
}