/* ================================================
   雷隼 LEISUN / 嘟嘟 DUDU  — Shared Design System
   Lithium battery charging equipment enterprise site
   ================================================ */

/* --- Color tokens --- */
:root {
  --bg:        oklch(12% 0.025 235);
  --bg-elev:   oklch(16% 0.030 232);
  --surface:   oklch(20% 0.028 230);
  --surface-2: oklch(24% 0.032 225);

  --fg:        oklch(95% 0.010 215);
  --muted:     oklch(70% 0.030 220);
  --dim:       oklch(52% 0.025 220);
  --border:    oklch(100% 0 0 / 0.12);
  --border-s:  oklch(100% 0 0 / 0.22);

  --accent:    oklch(72% 0.150 175);
  --accent-2:  oklch(68% 0.130 200);
  --warn:      oklch(76% 0.130 74);
  --danger:    oklch(65% 0.180 28);

  --font-display: "Microsoft YaHei UI", "PingFang SC", "Noto Sans SC", system-ui, sans-serif;
  --font-body:    "Microsoft YaHei UI", "PingFang SC", "Noto Sans SC", system-ui, sans-serif;
  --font-mono:    "Cascadia Mono", "JetBrains Mono", Consolas, "Courier New", monospace;

  --radius-s: 4px;
  --radius-m: 8px;
  --radius-l: 12px;
  --radius-xl: 18px;

  --shadow: oklch(5% 0.02 235 / 0.50);
  --glow:   oklch(72% 0.150 175 / 0.18);
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--fg);
  background: var(--bg);
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* --- Typography --- */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; line-height: 1.2; }
h1 { font-size: clamp(36px, 5vw, 64px); letter-spacing: -0.01em; }
h2 { font-size: clamp(28px, 3.5vw, 48px); letter-spacing: -0.005em; }
h3 { font-size: clamp(20px, 2.5vw, 32px); }

/* --- Layout --- */
.container { width: min(1280px, 100% - 48px); margin: 0 auto; }
.section { padding: clamp(64px, 8vw, 120px) 0; }
.section + .section { border-top: 1px solid var(--border); }

/* --- Grid helpers --- */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

/* --- Cards --- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-m);
  padding: 32px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.card:hover {
  border-color: var(--border-s);
  box-shadow: 0 8px 32px var(--shadow);
}

/* --- Badge / pill --- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  color: var(--muted);
  background: oklch(100% 0 0 / 0.04);
}
.badge.accent {
  color: var(--accent);
  border-color: color-mix(in oklch, var(--accent), transparent 60%);
  background: color-mix(in oklch, var(--accent), transparent 90%);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 48px;
  padding: 0 28px;
  border-radius: var(--radius-s);
  font-weight: 700;
  font-size: 15px;
  border: 1px solid var(--border);
  background: oklch(100% 0 0 / 0.06);
  color: var(--fg);
  cursor: pointer;
  transition: all 0.2s ease;
}
.btn:hover {
  border-color: var(--accent);
  background: oklch(100% 0 0 / 0.1);
  transform: translateY(-1px);
}
.btn.primary {
  color: oklch(8% 0.02 230);
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-color: transparent;
  box-shadow: 0 12px 40px color-mix(in oklch, var(--accent), transparent 74%);
}
.btn.primary:hover {
  background: linear-gradient(135deg, var(--accent-2), var(--accent));
  transform: translateY(-2px);
}

/* --- Eyebrow / kicker --- */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 16px;
}

/* --- Stat number --- */
.stat { font-family: var(--font-mono); font-weight: 700; }
.stat.lg { font-size: clamp(36px, 4vw, 56px); }
.stat.sm { font-size: clamp(22px, 2.5vw, 32px); }

/* --- Section label --- */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 24px;
}
.section-label .bar {
  width: 24px;
  height: 3px;
  background: var(--accent);
  border-radius: 2px;
}
.section-label span {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  color: var(--muted);
}

/* --- Data table --- */
.spec-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
}
.spec-table th,
.spec-table td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.spec-table th {
  font-weight: 700;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: 0.08em;
}
.spec-table tr:hover td { background: oklch(100% 0 0 / 0.02); }
.spec-table .mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

/* --- Glow decoration --- */
.glow-line {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0.3;
}

/* --- Grid background --- */
.bg-grid {
  background-image:
    linear-gradient(to right, oklch(100% 0 0 / 0.04) 1px, transparent 1px),
    linear-gradient(to bottom, oklch(100% 0 0 / 0.035) 1px, transparent 1px);
  background-size: 64px 64px;
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .container { width: calc(100% - 32px); }
  .section { padding: clamp(48px, 6vw, 80px) 0; }
}
@media (max-width: 480px) {
  .container { padding: 0 16px; }
}

/* --- Reduced motion --- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}