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

html {
  scroll-behavior: smooth;
}

:root {
  --bg-primary: #ffffff;
  --bg-secondary: #fafafa;
  --bg-surface: #ffffff;
  --text-primary: #000000;
  --text-secondary: #666666;
  --text-muted: #999999;
  --border-light: #e0e0e0;
  --border-medium: #cccccc;
  --accent: #000000;
  --accent-hover: #333333;
  --btn-primary-bg: #000000;
  --btn-primary-text: #ffffff;
  --btn-secondary-bg: #ffffff;
  --btn-secondary-text: #000000;
  --btn-secondary-border: #000000;
  --card-bg: #ffffff;
  --card-border: #e0e0e0;
  --card-shadow: rgba(0, 0, 0, 0.08);
  --nav-bg: #ffffff;
  --nav-border: #e0e0e0;
  --scrollbar-track: #ffffff;
  --scrollbar-thumb: #cccccc;
  --selection-bg: #000000;
  --selection-text: #ffffff;
  --code-bg: #f5f5f5;
  --code-text: #000000;
}

[data-theme="dark"] {
  --bg-primary: #0a0a0a;
  --bg-secondary: #111111;
  --bg-surface: #0f0f0f;
  --text-primary: #ffffff;
  --text-secondary: #a0a0a0;
  --text-muted: #666666;
  --border-light: #1f1f1f;
  --border-medium: #333333;
  --accent: #ffffff;
  --accent-hover: #e0e0e0;
  --btn-primary-bg: #ffffff;
  --btn-primary-text: #000000;
  --btn-secondary-bg: #0a0a0a;
  --btn-secondary-text: #ffffff;
  --btn-secondary-border: #333333;
  --card-bg: #111111;
  --card-border: #1f1f1f;
  --card-shadow: rgba(0, 0, 0, 0.3);
  --nav-bg: #0a0a0a;
  --nav-border: #1f1f1f;
  --scrollbar-track: #0a0a0a;
  --scrollbar-thumb: #333333;
  --selection-bg: #ffffff;
  --selection-text: #000000;
  --code-bg: #1a1a1a;
  --code-text: #ffffff;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background 0.3s ease, color 0.3s ease;
}

::selection {
  background: var(--selection-bg);
  color: var(--selection-text);
}

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

a:hover {
  opacity: 0.7;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
}

.section-label {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 3px;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.section-title {
  font-size: clamp(32px, 5vw, 48px);
  font-weight: 700;
  line-height: 1.1;
  margin-bottom: 16px;
  letter-spacing: -1px;
}

.section-description {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 500px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  font-size: 14px;
  font-weight: 600;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-text);
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: var(--btn-primary-text);
  opacity: 1;
}

.btn-secondary {
  background: var(--btn-secondary-bg);
  color: var(--btn-secondary-text);
  border: 1px solid var(--btn-secondary-border);
}

.btn-secondary:hover {
  background: var(--btn-primary-bg);
  color: var(--btn-primary-text);
  opacity: 1;
}

::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

@media (max-width: 768px) {
  .section {
    padding: 80px 0;
  }
}