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

:root {
  --bg: #0f0f14;
  --surface: #1a1a24;
  --surface-hover: #22222e;
  --text: #e0e0e8;
  --text-dim: #8888a0;
  --accent: #6c8cff;
  --accent-glow: rgba(108, 140, 255, 0.15);
  --border: #2a2a38;
  --radius: 12px;
  --sidebar-w: 220px;
}

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  min-height: 100vh;
  line-height: 1.6;
}

.sidebar {
  width: var(--sidebar-w);
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 24px 16px;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 10;
}

.logo {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--accent);
  margin-bottom: 32px;
  padding-left: 8px;
}

.nav-links {
  list-style: none;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav-btn {
  width: 100%;
  text-align: left;
  padding: 10px 12px;
  border: none;
  border-radius: 8px;
  background: transparent;
  color: var(--text-dim);
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s;
}

.nav-btn:hover { background: var(--surface-hover); color: var(--text); }
.nav-btn.active { background: var(--accent-glow); color: var(--accent); font-weight: 600; }

.sidebar-footer {
  font-size: 0.78rem;
  color: var(--text-dim);
  padding: 16px 8px 0;
  border-top: 1px solid var(--border);
  margin-top: 16px;
}

.content {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 48px 56px;
  max-width: 960px;
}

.page { display: none; }
.page.active { display: block; animation: fadeIn 0.35s ease; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

.hero { padding-top: 80px; }
.hero h1 { font-size: 2.6rem; font-weight: 700; margin-bottom: 16px; }
.hero .highlight { color: var(--accent); }
.hero .subtitle { font-size: 1.2rem; color: var(--text-dim); margin-bottom: 12px; }
.hero .intro { color: var(--text-dim); margin-bottom: 32px; max-width: 480px; }
.hero-links { display: flex; gap: 12px; }

.btn {
  display: inline-block;
  padding: 10px 24px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: opacity 0.2s;
}
.btn:hover { opacity: 0.85; }
.btn-outline { background: transparent; border: 1.5px solid var(--border); color: var(--text); }
.btn-outline:hover { border-color: var(--accent); }

h2 { font-size: 1.8rem; margin-bottom: 8px; }
.section-desc { color: var(--text-dim); margin-bottom: 32px; }

.card-list { display: flex; flex-direction: column; gap: 14px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  transition: border-color 0.2s, transform 0.2s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); }

.card-date { font-size: 0.8rem; color: var(--text-dim); display: block; margin-bottom: 6px; }
.card h3 { font-size: 1.1rem; margin-bottom: 6px; }
.card p { color: var(--text-dim); font-size: 0.9rem; margin-bottom: 10px; }
.card-tag { font-size: 0.78rem; background: var(--accent-glow); color: var(--accent); padding: 2px 10px; border-radius: 20px; }
.card-icon { font-size: 2rem; margin-bottom: 10px; }

.shop-card { text-align: center; }
.shop-img { font-size: 3rem; margin-bottom: 12px; }
.price { font-size: 1.1rem; font-weight: 700; color: var(--accent); }

.notes-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.notes-category {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
}
.notes-category h3 { margin-bottom: 10px; color: var(--accent); }
.notes-category ul { list-style: none; display: flex; flex-direction: column; gap: 6px; }
.notes-category li { color: var(--text-dim); font-size: 0.9rem; padding-left: 12px; position: relative; }
.notes-category li::before { content: "\203A"; position: absolute; left: 0; color: var(--accent); }

@media (max-width: 768px) {
  .sidebar { width: 60px; padding: 16px 8px; }
  .sidebar .logo { font-size: 1rem; text-align: center; padding: 0; }
  .nav-btn { font-size: 0; text-align: center; padding: 10px 0; }
  .nav-btn::first-letter { font-size: 1.2rem; }
  .sidebar-footer { display: none; }
  .content { margin-left: 60px; padding: 24px 20px; }
  .hero { padding-top: 40px; }
  .hero h1 { font-size: 1.6rem; }
  .grid-2, .grid-3 { grid-template-columns: 1fr; }
  .notes-grid { grid-template-columns: 1fr; }
}