/* ============================================
   PowerStorage.cn — 储能技术前沿
   Design: Grand Minimalist / Editorial
   Themes: Dark (default) + Light (Claude-inspired)
   ============================================ */

/* --- Design Tokens: Dark Theme (default) --- */
:root {
  --bg: #070b12;
  --bg-elevated: #0d1320;
  --bg-card: #111827;
  --bg-card-hover: #161e30;
  --border: rgba(255, 255, 255, 0.06);
  --border-strong: rgba(255, 255, 255, 0.1);
  --text: #e6ecf4;
  --text-secondary: #8899b8;
  --text-muted: #506080;
  --accent: #3b9eff;
  --accent-soft: rgba(59, 158, 255, 0.12);
  --accent-glow: rgba(59, 158, 255, 0.25);
  --accent2: #a78bfa;
  --accent2-soft: rgba(167, 139, 250, 0.12);
  --green: #34d399;
  --green-soft: rgba(52, 211, 153, 0.12);
  --amber: #fbbf24;
  --amber-soft: rgba(251, 191, 36, 0.12);
  --red: #f87171;
  --heading-color: #fff;
  --strong-color: #fff;
  --topbar-bg: rgba(7, 11, 18, 0.82);
  --topbar-border: rgba(255, 255, 255, 0.06);
  --dropdown-bg: #111827;
  --dropdown-shadow: 0 20px 60px rgba(0,0,0,0.5);
  --btn-hover-bg: rgba(255,255,255,0.04);
  --table-hover-bg: rgba(255,255,255,0.02);
  --code-color: #a78bfa;
  --scrollbar-thumb: rgba(255,255,255,0.08);
  --scrollbar-thumb-hover: rgba(255,255,255,0.15);
  --overlay-bg: rgba(0,0,0,0.5);
  --stat-value-color: #fff;
  --font: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
  --radius: 10px;
  --radius-lg: 16px;
  --max-w: 820px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Design Tokens: Light Theme --- */
[data-theme="light"] {
  --bg: #f9f7f4;
  --bg-elevated: #ffffff;
  --bg-card: #ffffff;
  --bg-card-hover: #faf8f5;
  --border: rgba(0, 0, 0, 0.07);
  --border-strong: rgba(0, 0, 0, 0.12);
  --text: #1a1817;
  --text-secondary: #5c554d;
  --text-muted: #9c958d;
  --accent: #d97706;
  --accent-soft: rgba(217, 119, 6, 0.08);
  --accent-glow: rgba(217, 119, 6, 0.15);
  --accent2: #7c3aed;
  --accent2-soft: rgba(124, 58, 237, 0.08);
  --green: #059669;
  --green-soft: rgba(5, 150, 105, 0.08);
  --amber: #d97706;
  --amber-soft: rgba(217, 119, 6, 0.08);
  --red: #dc2626;
  --heading-color: #171410;
  --strong-color: #171410;
  --topbar-bg: rgba(249, 247, 244, 0.88);
  --topbar-border: rgba(0, 0, 0, 0.07);
  --dropdown-bg: #ffffff;
  --dropdown-shadow: 0 12px 40px rgba(0,0,0,0.08), 0 2px 8px rgba(0,0,0,0.04);
  --btn-hover-bg: rgba(0,0,0,0.04);
  --table-hover-bg: rgba(0,0,0,0.02);
  --code-color: #7c3aed;
  --scrollbar-thumb: rgba(0,0,0,0.12);
  --scrollbar-thumb-hover: rgba(0,0,0,0.2);
  --overlay-bg: rgba(0,0,0,0.25);
  --stat-value-color: #171410;
}

/* --- Reset --- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.8;
  min-height: 100vh;
  transition: background 0.3s ease, color 0.3s ease;
}

/* --- Topbar --- */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: 56px;
  background: var(--topbar-bg);
  backdrop-filter: blur(16px) saturate(140%);
  -webkit-backdrop-filter: blur(16px) saturate(140%);
  border-bottom: 1px solid var(--topbar-border);
  transition: background 0.3s ease, border-color 0.3s ease;
}

.topbar-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 28px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.3px;
}

.logo-svg { color: var(--accent); }
.logo-domain { color: var(--text-muted); font-weight: 400; font-size: 0.82rem; }

/* Topbar right group */
.topbar-right { display: flex; align-items: center; gap: 8px; }

/* --- Theme Toggle --- */
.theme-toggle {
  width: 36px; height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--transition);
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--text);
  background: var(--btn-hover-bg);
  border-color: var(--accent);
}

.theme-toggle svg { width: 18px; height: 18px; transition: transform 0.4s ease; }

.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

[data-theme="light"] .theme-toggle .icon-sun { display: block; }
[data-theme="light"] .theme-toggle .icon-moon { display: none; }

/* Topbar Nav */
.topbar-nav { display: flex; gap: 2px; }

.nav-dropdown { position: relative; }

.nav-dropdown-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 500;
  padding: 7px 14px;
  border-radius: 7px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: all var(--transition);
}

.nav-dropdown-btn:hover { color: var(--text); background: var(--btn-hover-bg); }
.nav-dropdown-btn .arrow { font-size: 0.55rem; opacity: 0.5; transition: transform var(--transition); }
.nav-dropdown:hover .nav-dropdown-btn .arrow { transform: rotate(180deg); }

.nav-dropdown-panel {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(8px);
  background: var(--dropdown-bg);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 6px;
  min-width: 180px;
  opacity: 0;
  visibility: hidden;
  transition: all 0.2s ease;
  box-shadow: var(--dropdown-shadow);
}

.nav-dropdown:hover .nav-dropdown-panel { opacity: 1; visibility: visible; transform: translateX(-50%) translateY(4px); }

.nav-dropdown-panel a {
  display: block;
  padding: 7px 12px;
  font-size: 0.83rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 6px;
  transition: all var(--transition);
  white-space: nowrap;
}

.nav-dropdown-panel a:hover { color: var(--text); background: var(--accent-soft); }
.nav-dropdown-panel a.active { color: var(--accent); background: var(--accent-soft); font-weight: 500; }

/* Mobile */
.mobile-menu-btn {
  display: none;
  width: 34px; height: 34px;
  background: none;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  cursor: pointer;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 8px;
}

.mobile-menu-btn span { display: block; width: 16px; height: 1.5px; background: var(--text); border-radius: 1px; }

.mobile-drawer {
  position: fixed;
  top: 0; right: 0;
  width: 300px; height: 100vh;
  background: var(--bg-elevated);
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  overflow-y: auto;
  padding: 76px 24px 40px;
  border-left: 1px solid var(--border);
}

.mobile-drawer.open { transform: translateX(0); }
.mobile-drawer-overlay {
  position: fixed; inset: 0;
  background: var(--overlay-bg);
  z-index: 199;
  opacity: 0; visibility: hidden;
  transition: all 0.3s ease;
}
.mobile-drawer-overlay.open { opacity: 1; visibility: visible; }

.mobile-nav-section { margin-bottom: 28px; }
.mobile-nav-section h3 {
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  color: var(--text-muted);
  margin-bottom: 10px;
  font-weight: 600;
}
.mobile-nav-section a {
  display: block;
  padding: 8px 0;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.88rem;
  border-bottom: 1px solid var(--border);
  transition: color var(--transition);
}
.mobile-nav-section a:hover { color: var(--accent); }

/* --- Main --- */
.main {
  padding-top: 56px;
  min-height: calc(100vh - 120px);
}

/* --- Loading --- */
.loading-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 60vh;
  gap: 16px;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.loading-ring {
  width: 32px; height: 32px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ============================================
   Content Styles
   ============================================ */

.content { animation: fadeUp 0.4s ease; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(18px); } to { opacity: 1; transform: translateY(0); } }

/* Hero h1 */
.content > h1:first-child {
  font-size: clamp(2rem, 5vw, 2.8rem);
  font-weight: 800;
  letter-spacing: -0.8px;
  line-height: 1.2;
  margin: 48px 0 16px;
  padding: 0 32px;
  max-width: var(--max-w);
  margin-left: auto;
  margin-right: auto;
  color: var(--heading-color);
}

/* Subtitle (first blockquote after h1) */
.content > h1:first-child + blockquote {
  max-width: var(--max-w);
  margin: 0 auto 48px;
  padding: 0 32px;
  border: none;
  background: none;
  font-size: 1.1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  font-style: normal;
}

.content > h1:first-child + blockquote p {
  font-style: normal;
  color: var(--text-secondary);
}

/* Content body wrapper */
.content > h2,
.content > h3,
.content > h4,
.content > p,
.content > ul,
.content > ol,
.content > table,
.content > pre,
.content > hr,
.content > blockquote:not(:first-child) {
  max-width: var(--max-w);
  margin-left: auto;
  margin-right: auto;
  padding-left: 32px;
  padding-right: 32px;
}

/* --- Headings --- */
.content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 52px;
  margin-bottom: 18px;
  color: var(--heading-color);
  letter-spacing: -0.3px;
}

.content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-top: 34px;
  margin-bottom: 10px;
  color: var(--accent);
}

.content h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-top: 22px;
  margin-bottom: 8px;
  color: var(--text);
}

/* --- Paragraph --- */
.content p {
  margin-bottom: 16px;
  color: var(--text-secondary);
  font-size: 0.93rem;
  line-height: 1.85;
}

/* --- Blockquote --- */
.content blockquote {
  margin-top: 26px;
  margin-bottom: 26px;
  padding: 18px 22px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.content blockquote p { color: var(--text); margin: 0; font-size: 0.88rem; }

/* --- Strong / Emphasis --- */
.content strong { color: var(--strong-color); font-weight: 600; }
.content em { color: var(--accent); font-style: normal; }

/* --- Links --- */
.content a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid var(--accent-soft);
  transition: border-color var(--transition);
}

.content a:hover { border-bottom-color: var(--accent); }

/* --- Tables --- */
.content table {
  margin-top: 26px;
  margin-bottom: 26px;
  border-collapse: collapse;
  font-size: 0.84rem;
  width: calc(100% - 64px);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-strong);
}

.content thead { background: var(--bg-card); }

.content th {
  padding: 12px 16px;
  text-align: left;
  font-weight: 600;
  color: var(--accent);
  font-size: 0.73rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  border-bottom: 1px solid var(--border-strong);
}

.content td {
  padding: 11px 16px;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
  vertical-align: top;
}

.content tr:last-child td { border-bottom: none; }
.content tbody tr:hover td { background: var(--table-hover-bg); }

/* --- Lists --- */
.content ul, .content ol { margin-top: 16px; margin-bottom: 16px; padding-left: 26px; }
.content li { margin-bottom: 7px; font-size: 0.91rem; color: var(--text-secondary); }
.content li::marker { color: var(--accent); }

/* --- Code --- */
.content code {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  background: var(--bg-card);
  padding: 2px 7px;
  border-radius: 5px;
  color: var(--code-color);
  border: 1px solid var(--border);
}

.content pre {
  margin-top: 22px;
  margin-bottom: 22px;
  padding: 18px 22px;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  overflow-x: auto;
}

.content pre code { background: none; border: none; padding: 0; color: var(--text-secondary); }

/* --- HR --- */
.content hr { margin: 44px auto; border: none; height: 1px; background: var(--border); max-width: var(--max-w); }

/* ============================================
   Stats Banner
   ============================================ */
.stats-banner {
  max-width: var(--max-w);
  margin: 0 auto 52px;
  padding: 0 32px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px 24px;
  transition: all var(--transition);
}

.stat-card:hover {
  border-color: var(--border-strong);
  background: var(--bg-card-hover);
  transform: translateY(-2px);
}

.stat-value {
  font-size: 1.9rem;
  font-weight: 800;
  letter-spacing: -1px;
  color: var(--stat-value-color);
  line-height: 1;
  margin-bottom: 6px;
}

.stat-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
}

.stat-card.accent .stat-value { color: var(--accent); }
.stat-card.green .stat-value { color: var(--green); }
.stat-card.purple .stat-value { color: var(--accent2); }

/* ============================================
   Footer
   ============================================ */
.footer {
  border-top: 1px solid var(--border);
  margin-top: 80px;
  padding: 28px 0;
}

.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-logo { font-weight: 700; color: var(--text); font-size: 0.9rem; }
.footer-brand p { font-size: 0.75rem; color: var(--text-muted); margin-top: 3px; }
.footer-meta { display: flex; align-items: center; gap: 10px; font-size: 0.75rem; color: var(--text-muted); }
.footer-dot { width: 4px; height: 4px; border-radius: 50%; background: var(--text-muted); }

/* ============================================
   Scrollbar
   ============================================ */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--scrollbar-thumb-hover); }

/* ============================================
   Theme transition helpers
   ============================================ */
.topbar, .stat-card, .nav-dropdown-panel, .content blockquote,
.content pre, .content code, .content table, .mobile-drawer {
  transition: background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .topbar-nav { display: none; }
  .mobile-menu-btn { display: flex; }
  .topbar-inner { padding: 0 14px; }

  .stats-banner {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .stat-value { font-size: 1.4rem; }

  .content > h1:first-child {
    font-size: 1.5rem;
    padding: 0 16px;
  }

  .content > h1:first-child + blockquote {
    font-size: 0.9rem;
    padding: 0 16px;
    margin-bottom: 28px;
  }

  .content > h2,
  .content > h3,
  .content > p,
  .content > ul,
  .content > ol,
  .content > table,
  .content > pre,
  .content > hr,
  .content > blockquote:not(:first-child) {
    padding-left: 16px;
    padding-right: 16px;
  }

  .content table { width: calc(100% - 32px); font-size: 0.73rem; }
  .content th, .content td { padding: 8px 10px; }

  .footer-inner { flex-direction: column; align-items: flex-start; padding: 0 16px; }
}

@media (max-width: 480px) {
  .content h2 { font-size: 1.25rem; }
}