/* ============================================================
   BASE.CSS — Design System Foundation
   Reset, Custom Properties, Typography, Global Tokens
   ============================================================ */

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  font-size: 16px;
}

body {
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

table {
  border-collapse: collapse;
  border-spacing: 0;
}

/* ---------- Custom Properties (Design Tokens) ---------- */
:root {
  /* --- Backgrounds --- */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a2e;
  --bg-elevated: #1e1e30;
  --bg-glass: rgba(255, 255, 255, 0.03);
  --bg-glass-hover: rgba(255, 255, 255, 0.06);
  --bg-input: rgba(255, 255, 255, 0.04);
  --bg-input-focus: rgba(255, 255, 255, 0.07);

  /* --- Borders --- */
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-default: rgba(255, 255, 255, 0.1);
  --border-active: rgba(99, 102, 241, 0.4);
  --border-radius-sm: 6px;
  --border-radius-md: 10px;
  --border-radius-lg: 16px;
  --border-radius-xl: 24px;
  --border-radius-full: 9999px;

  /* --- Text --- */
  --text-primary: #f0f0f5;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --text-inverse: #0a0a0f;

  /* --- Accent Colors --- */
  --accent-primary: #6366f1;
  --accent-primary-hover: #818cf8;
  --accent-secondary: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #6366f1, #8b5cf6);
  --accent-gradient-hover: linear-gradient(135deg, #818cf8, #a78bfa);
  --accent-glow: 0 0 20px rgba(99, 102, 241, 0.3);
  --accent-glow-strong: 0 0 40px rgba(99, 102, 241, 0.4);

  /* --- Semantic Colors --- */
  --success: #10b981;
  --success-bg: rgba(16, 185, 129, 0.1);
  --success-border: rgba(16, 185, 129, 0.3);
  --warning: #f59e0b;
  --warning-bg: rgba(245, 158, 11, 0.1);
  --warning-border: rgba(245, 158, 11, 0.3);
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.1);
  --error-border: rgba(239, 68, 68, 0.3);
  --info: #3b82f6;
  --info-bg: rgba(59, 130, 246, 0.1);
  --info-border: rgba(59, 130, 246, 0.3);

  /* --- Chip/Tag Colors --- */
  --chip-bg: rgba(99, 102, 241, 0.1);
  --chip-border: rgba(99, 102, 241, 0.2);
  --chip-active-bg: rgba(99, 102, 241, 0.25);
  --chip-active-border: rgba(99, 102, 241, 0.5);
  --chip-text: #c7d2fe;

  /* --- Shadows --- */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 16px 64px rgba(0, 0, 0, 0.6);
  --shadow-inner: inset 0 1px 4px rgba(0, 0, 0, 0.3);

  /* --- Glassmorphism --- */
  --glass-bg: rgba(18, 18, 26, 0.7);
  --glass-blur: blur(20px);
  --glass-border: 1px solid rgba(255, 255, 255, 0.08);

  /* --- Typography --- */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;

  --text-xs: 0.75rem;     /* 12px */
  --text-sm: 0.8125rem;   /* 13px */
  --text-base: 0.9375rem; /* 15px */
  --text-md: 1rem;        /* 16px */
  --text-lg: 1.125rem;    /* 18px */
  --text-xl: 1.25rem;     /* 20px */
  --text-2xl: 1.5rem;     /* 24px */
  --text-3xl: 1.875rem;   /* 30px */
  --text-4xl: 2.25rem;    /* 36px */
  --text-5xl: 3rem;       /* 48px */
  --text-6xl: 3.75rem;    /* 60px */

  --leading-tight: 1.2;
  --leading-normal: 1.6;
  --leading-relaxed: 1.8;

  --tracking-tight: -0.025em;
  --tracking-normal: 0;
  --tracking-wide: 0.025em;
  --tracking-wider: 0.05em;

  /* --- Spacing --- */
  --space-1: 0.25rem;   /* 4px */
  --space-2: 0.5rem;    /* 8px */
  --space-3: 0.75rem;   /* 12px */
  --space-4: 1rem;      /* 16px */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px */
  --space-8: 2rem;      /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */

  /* --- Layout --- */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1440px;
  --nav-height: 72px;
  --sidebar-width: 440px;

  /* --- Transitions --- */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
  --transition-spring: 300ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* --- Z-Index Scale --- */
  --z-base: 1;
  --z-dropdown: 10;
  --z-sticky: 20;
  --z-overlay: 30;
  --z-modal: 40;
  --z-toast: 50;
  --z-tooltip: 60;
}

/* ---------- Global Styles ---------- */
body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  background-image:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(99, 102, 241, 0.08), transparent),
    radial-gradient(ellipse 60% 40% at 80% 60%, rgba(139, 92, 246, 0.04), transparent);
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-4xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-md); }

p {
  color: var(--text-secondary);
  line-height: var(--leading-relaxed);
}

strong, b { font-weight: 600; }

small { font-size: var(--text-sm); }

.mono { font-family: var(--font-mono); }

/* ---------- Container ---------- */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.container-sm { max-width: var(--container-sm); }
.container-md { max-width: var(--container-md); }
.container-lg { max-width: var(--container-lg); }
.container-2xl { max-width: var(--container-2xl); }

/* ---------- Section ---------- */
.section {
  padding: var(--space-20) 0;
}

.section-sm {
  padding: var(--space-12) 0;
}

.section-lg {
  padding: var(--space-24) 0;
}

/* ---------- Links ---------- */
a {
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-primary-hover);
}

.link {
  color: var(--accent-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.link:hover {
  color: var(--accent-primary-hover);
  text-decoration-thickness: 2px;
}

/* ---------- Selection ---------- */
::selection {
  background: rgba(99, 102, 241, 0.3);
  color: var(--text-primary);
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* ---------- Focus Styles ---------- */
:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
  border-radius: var(--border-radius-sm);
}

/* ---------- Utility Classes ---------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

.text-center { text-align: center; }
.text-gradient {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

.grid { display: grid; }

.relative { position: relative; }
.absolute { position: absolute; }

.w-full { width: 100%; }

.hidden { display: none !important; }

/* ---------- Reveal Animations ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ---------- Responsive Utilities & Anti-Overflow Reset ---------- */
html, body {
  overflow-x: hidden;
  max-width: 100vw;
}

h1, h2, h3, h4, h5, h6, p, span, a, td, th, li {
  overflow-wrap: break-word;
  word-break: break-word;
}

img, svg, video, canvas {
  max-width: 100%;
  height: auto;
}

@media (max-width: 1024px) {
  h1 { font-size: clamp(2rem, 4vw, 2.75rem); }
  h2 { font-size: clamp(1.6rem, 3.2vw, 2.25rem); }
  h3 { font-size: var(--text-xl); }

  .section { padding: var(--space-12) 0; }
  .section-lg { padding: var(--space-16) 0; }
}

@media (max-width: 768px) {
  html { font-size: 15px; }

  h1 { font-size: clamp(1.75rem, 5vw, 2.25rem); }
  h2 { font-size: clamp(1.35rem, 4vw, 1.75rem); }
  h3 { font-size: var(--text-lg); }

  .container { padding: 0 var(--space-4); }
  .section { padding: var(--space-8) 0; }
  .section-lg { padding: var(--space-12) 0; }
}

@media (max-width: 480px) {
  html { font-size: 14px; }
  .container { padding: 0 var(--space-3); }
  h1 { font-size: clamp(1.5rem, 6vw, 1.85rem); }
  h2 { font-size: clamp(1.25rem, 5vw, 1.5rem); }
  h3 { font-size: var(--text-base); }
  .section { padding: var(--space-6) 0; }
}