:root {
  --bg-primary: #0a0e17;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.85);
  --bg-card-hover: rgba(30, 41, 59, 0.95);
  --border-color: rgba(0, 212, 255, 0.15);
  --border-glow: rgba(0, 212, 255, 0.4);
  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-cyan: #00d4ff;
  --accent-purple: #a855f7;
  --accent-green: #10b981;
  --accent-pink: #ec4899;
  --gradient-main: linear-gradient(135deg, #00d4ff 0%, #a855f7 50%, #ec4899 100%);
  --shadow-glow: 0 0 20px rgba(0, 212, 255, 0.15);
  --font-display: 'Orbitron', sans-serif;
  --font-body: 'Noto Sans SC', -apple-system, sans-serif;
  --radius: 12px;
  --radius-sm: 8px;
  --header-height: 72px;
}

[data-theme="light"] {
  --bg-primary: #f0f4f8;
  --bg-secondary: #ffffff;
  --bg-card: rgba(255, 255, 255, 0.9);
  --bg-card-hover: rgba(255, 255, 255, 1);
  --border-color: rgba(0, 120, 180, 0.15);
  --border-glow: rgba(0, 120, 180, 0.3);
  --text-primary: #1e293b;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --shadow-glow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  background-image:
    radial-gradient(ellipse at 20% 0%, rgba(0, 212, 255, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 100%, rgba(168, 85, 247, 0.08) 0%, transparent 50%),
    linear-gradient(rgba(0, 212, 255, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 212, 255, 0.03) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 40px 40px, 40px 40px;
}
a { color: var(--accent-cyan); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-purple); }

.site-header {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(10, 14, 23, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}
[data-theme="light"] .site-header { background: rgba(255, 255, 255, 0.92); }
.header-inner {
  max-width: 1400px; margin: 0 auto; padding: 0 24px;
  height: var(--header-height); display: flex; align-items: center; gap: 24px;
}
.logo { display: flex; align-items: center; gap: 12px; flex-shrink: 0; }
.logo-icon {
  width: 40px; height: 40px; flex-shrink: 0;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 10px; overflow: hidden;
  box-shadow: 0 0 0 1px rgba(240, 180, 41, 0.25);
}
.logo-icon svg { width: 40px; height: 40px; display: block; }
.logo-text h1 {
  font-family: var(--font-display); font-size: 1.25rem; font-weight: 700;
  background: var(--gradient-main); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}
.logo-text .tagline { font-size: 0.75rem; color: var(--text-muted); }
.main-nav { display: flex; flex-wrap: wrap; gap: 4px; flex: 1; overflow-x: auto; scrollbar-width: none; }
.main-nav::-webkit-scrollbar { display: none; }
.nav-link {
  padding: 6px 10px; font-size: 0.8rem; color: var(--text-secondary);
  border-radius: var(--radius-sm); white-space: nowrap; transition: all 0.2s;
}
.nav-link:hover { color: var(--accent-cyan); background: rgba(0, 212, 255, 0.1); }
.header-actions { display: flex; gap: 8px; }
.btn-icon {
  width: 36px; height: 36px; border: 1px solid var(--border-color);
  background: var(--bg-card); border-radius: var(--radius-sm); cursor: pointer;
  font-size: 1rem; transition: all 0.2s;
}
.btn-icon:hover { border-color: var(--accent-cyan); box-shadow: var(--shadow-glow); }
.search-panel { max-width: 1400px; margin: 0 auto; padding: 12px 24px 16px; border-bottom: 1px solid var(--border-color); }
.search-panel.hidden { display: none; }
#searchInput {
  width: 100%; padding: 12px 16px; background: var(--bg-secondary);
  border: 1px solid var(--border-color); border-radius: var(--radius);
  color: var(--text-primary); font-size: 1rem; outline: none;
}
#searchInput:focus { border-color: var(--accent-cyan); box-shadow: var(--shadow-glow); }
.search-results { margin-top: 8px; max-height: 300px; overflow-y: auto; }
.search-result-item { display: block; padding: 10px 16px; color: var(--text-primary); border-radius: var(--radius-sm); }
.search-result-item:hover { background: var(--bg-card-hover); }

.main-content { max-width: 1400px; margin: 0 auto; padding: 24px; }
.hero {
  position: relative; padding: 60px 24px; text-align: center;
  margin-bottom: 40px; border-radius: var(--radius); overflow: hidden;
  border: 1px solid var(--border-color);
}
.hero-bg { position: absolute; inset: 0; background: var(--gradient-main); opacity: 0.06; }
.hero-content { position: relative; z-index: 1; }
.hero-title {
  font-family: var(--font-display); font-size: 2.5rem; font-weight: 700;
  background: var(--gradient-main); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text; margin-bottom: 8px;
}
.hero-subtitle { font-size: 1.1rem; color: var(--text-secondary); margin-bottom: 16px; }
.hero-desc { max-width: 600px; margin: 0 auto 24px; color: var(--text-muted); font-size: 0.95rem; }
.hero-stats { display: flex; justify-content: center; gap: 32px; flex-wrap: wrap; }
.stat-item {
  padding: 8px 20px; background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: 999px; font-size: 0.9rem; color: var(--text-secondary);
}
.stat-item strong { color: var(--accent-cyan); font-family: var(--font-display); }

.category-section { margin-bottom: 48px; scroll-margin-top: calc(var(--header-height) + 16px); }
.section-header { margin-bottom: 20px; display: flex; flex-wrap: wrap; align-items: baseline; gap: 12px; }
.section-header h3 { font-family: var(--font-display); font-size: 1.3rem; }
.section-header p { flex: 1; color: var(--text-muted); font-size: 0.9rem; min-width: 200px; }
.view-all { font-size: 0.85rem; color: var(--accent-cyan); }
.tools-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.tool-card {
  display: flex; flex-direction: column; gap: 8px; padding: 20px;
  background: var(--bg-card); border: 1px solid var(--border-color);
  border-radius: var(--radius); transition: all 0.3s; position: relative; overflow: hidden;
}
.tool-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--gradient-main); opacity: 0; transition: opacity 0.3s;
}
.tool-card:hover {
  border-color: var(--border-glow); box-shadow: var(--shadow-glow);
  transform: translateY(-2px); background: var(--bg-card-hover);
}
.tool-card:hover::before { opacity: 1; }
.tool-name { font-weight: 500; color: var(--text-primary); font-size: 0.95rem; }
.tool-desc {
  font-size: 0.8rem; color: var(--text-muted); line-height: 1.5;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}

.breadcrumb { padding: 12px 0; font-size: 0.85rem; color: var(--text-muted); display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--accent-cyan); }
.tool-page { padding-bottom: 40px; }
.tool-header { margin-bottom: 24px; padding: 24px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); }
.tool-header h2 { font-family: var(--font-display); font-size: 1.5rem; margin-bottom: 8px; color: var(--accent-cyan); }
.tool-description { color: var(--text-secondary); font-size: 0.95rem; }
.tool-workspace { padding: 24px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); min-height: 300px; }

.tool-panel { display: flex; flex-direction: column; gap: 16px; }
.tool-row { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.tool-label { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 4px; display: block; }
.tool-input, .tool-textarea, .tool-select {
  width: 100%; padding: 12px 16px; background: var(--bg-secondary);
  border: 1px solid var(--border-color); border-radius: var(--radius-sm);
  color: var(--text-primary); font-family: var(--font-body); font-size: 0.95rem; outline: none;
}
.tool-textarea { min-height: 160px; resize: vertical; font-family: Consolas, monospace; }
.tool-input:focus, .tool-textarea:focus, .tool-select:focus { border-color: var(--accent-cyan); box-shadow: var(--shadow-glow); }
.btn-primary, .btn-secondary, .btn-group button {
  padding: 10px 20px; border: none; border-radius: var(--radius-sm);
  font-size: 0.9rem; cursor: pointer; transition: all 0.2s; font-family: var(--font-body);
}
.btn-primary { background: var(--gradient-main); color: #fff; font-weight: 500; }
.btn-primary:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-secondary { background: var(--bg-secondary); color: var(--text-primary); border: 1px solid var(--border-color); }
.btn-secondary:hover { border-color: var(--accent-cyan); }
.btn-group { display: flex; flex-wrap: wrap; gap: 8px; }
.btn-group button.btn-primary { box-shadow: 0 0 12px rgba(0, 212, 255, 0.35); }
.btn-group button.btn-secondary:active { transform: translateY(1px); }
.tool-result {
  padding: 16px; background: var(--bg-secondary); border: 1px solid var(--border-color);
  border-radius: var(--radius-sm); font-family: Consolas, monospace; font-size: 0.9rem;
  white-space: pre-wrap; word-break: break-all; min-height: 60px;
}
.tool-result.success { border-color: var(--accent-green); }
.tool-result.error { border-color: var(--accent-pink); color: var(--accent-pink); }
.tool-grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 768px) { .tool-grid-2 { grid-template-columns: 1fr; } }
.tool-info {
  padding: 12px 16px; background: rgba(0, 212, 255, 0.08);
  border-left: 3px solid var(--accent-cyan); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: 0.85rem; color: var(--text-secondary);
}
.tool-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.tool-table th, .tool-table td { padding: 10px 12px; border: 1px solid var(--border-color); text-align: left; }
.tool-table th { background: var(--bg-secondary); color: var(--accent-cyan); font-weight: 500; }
.tool-table tr:hover td { background: rgba(0, 212, 255, 0.05); }
.symbol-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(48px, 1fr)); gap: 8px; }
.symbol-item {
  display: flex; align-items: center; justify-content: center; padding: 12px;
  background: var(--bg-secondary); border: 1px solid var(--border-color);
  border-radius: var(--radius-sm); cursor: pointer; font-size: 1.2rem; transition: all 0.2s;
}
.symbol-item:hover { border-color: var(--accent-cyan); transform: scale(1.1); }
.color-preview { width: 60px; height: 60px; border-radius: var(--radius-sm); border: 2px solid var(--border-color); }
.qr-output, .barcode-output { display: flex; justify-content: center; padding: 20px; background: #fff; border-radius: var(--radius-sm); margin-top: 12px; }
.tool-workspace canvas { max-width: 100%; background: #fff; border-radius: var(--radius-sm); margin-top: 8px; }
.tool-workspace svg { max-width: 100%; margin-top: 8px; background: #fff; padding: 12px; border-radius: var(--radius-sm); }
.loading { text-align: center; padding: 40px; color: var(--text-muted); }

.category-page { padding-bottom: 40px; }
.category-header { margin-bottom: 24px; padding: 24px; background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); }
.category-header h2 { font-family: var(--font-display); font-size: 1.5rem; margin-bottom: 8px; }
.error-page { text-align: center; padding: 80px 24px; }
.error-code {
  font-family: var(--font-display); font-size: 6rem; font-weight: 700;
  background: var(--gradient-main); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}
.error-page h2 { margin: 16px 0; }
.error-page p { color: var(--text-muted); margin-bottom: 24px; }

.site-footer {
  margin-top: 60px; padding: 40px 24px 24px;
  border-top: 1px solid var(--border-color); background: rgba(10, 14, 23, 0.5);
}
[data-theme="light"] .site-footer { background: rgba(240, 244, 248, 0.5); }
.footer-inner { max-width: 1400px; margin: 0 auto; display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 24px; }
.footer-brand { font-family: var(--font-display); font-size: 1rem; color: var(--accent-cyan); margin-bottom: 8px; }
.footer-desc { font-size: 0.85rem; color: var(--text-muted); }
.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-links a { color: var(--text-secondary); font-size: 0.85rem; }
.footer-date { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 4px; }
.copyright { font-size: 0.8rem; color: var(--text-muted); }
.back-to-top {
  position: fixed; bottom: 24px; right: 24px; width: 44px; height: 44px;
  border-radius: 50%; background: var(--gradient-main); color: #fff; border: none;
  cursor: pointer; font-size: 1.2rem; opacity: 0; visibility: hidden; transition: all 0.3s; z-index: 999;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top:hover { transform: translateY(-3px); }
.tool-checkbox { display: flex; align-items: center; gap: 8px; font-size: 0.9rem; color: var(--text-secondary); cursor: pointer; }
.tool-checkbox input { accent-color: var(--accent-cyan); }
.stopwatch-display { font-family: var(--font-display); font-size: 3rem; text-align: center; color: var(--accent-cyan); padding: 24px; letter-spacing: 4px; }
.reaction-box {
  width: 100%; height: 200px; display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius); font-size: 1.5rem; font-weight: 500; cursor: pointer;
  transition: background 0.2s; user-select: none;
}
.reaction-box.waiting { background: #ef4444; color: #fff; }
.reaction-box.ready { background: #22c55e; color: #fff; }
.reaction-box.too-soon { background: #f59e0b; color: #fff; }

@media (max-width: 1024px) { .footer-inner { grid-template-columns: 1fr; } .main-nav { display: none; } .hero-title { font-size: 1.8rem; } }
@media (max-width: 640px) { .header-inner { padding: 0 16px; } .main-content { padding: 16px; } .tools-grid { grid-template-columns: 1fr; } }