/* ============================================
   COLOR VARIABLES & DESIGN TOKENS
   Inspired by: Caltech, KAIST, Yonsei University
   ============================================ */

:root {
  /* ── Primary Colors (KAIST Blue) ── */
  --color-primary: #004191;
  --color-primary-light: #1a5ba8;
  --color-primary-dark: #003070;
  --color-primary-rgb: 0, 65, 145;

  /* ── Secondary Colors (Yonsei Royal Blue) ── */
  --color-secondary: #003876;
  --color-secondary-light: #1a5290;
  --color-secondary-dark: #002555;
  --color-secondary-rgb: 0, 56, 118;

  /* ── Accent Colors (Caltech Orange) ── */
  --color-accent: #FF6C0C;
  --color-accent-light: #FF8A3D;
  --color-accent-dark: #E05500;
  --color-accent-rgb: 255, 108, 12;

  /* ── Progress Bar Colors (by percentage) ── */
  --progress-0-25: #E31937;     /* Red - 초기 단계 */
  --progress-26-50: #FF6C0C;    /* Orange - 진행 중 */
  --progress-51-75: #004191;    /* Blue - 중반 이후 */
  --progress-76-100: #00843D;   /* Green - 거의 완료 */

  /* ── Neutral Colors ── */
  --color-white: #FFFFFF;
  --color-gray-50: #F8F9FA;
  --color-gray-100: #F1F3F5;
  --color-gray-200: #E9ECEF;
  --color-gray-300: #DEE2E6;
  --color-gray-400: #CED4DA;
  --color-gray-500: #ADB5BD;
  --color-gray-600: #868E96;
  --color-gray-700: #495057;
  --color-gray-800: #343A40;
  --color-gray-900: #212529;
  --color-black: #000000;

  /* ── Background Colors ── */
  --bg-primary: #FFFFFF;
  --bg-secondary: #F8F9FA;
  --bg-dark: #0A1628;
  --bg-hero: linear-gradient(135deg, #003876 0%, #004191 50%, #1a5ba8 100%);

  /* ── Text Colors ── */
  --text-primary: #212529;
  --text-secondary: #495057;
  --text-muted: #868E96;
  --text-light: #FFFFFF;
  --text-accent: #FF6C0C;

  /* ── Typography ── */
  --font-primary: 'Inter', 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-heading: 'Plus Jakarta Sans', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* ── Spacing ── */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* ── Border Radius ── */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* ── Shadows ── */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* ── Transitions ── */
  --transition-fast: 150ms ease;
  --transition-base: 300ms ease;
  --transition-slow: 500ms ease;

  /* ── Layout ── */
  --container-max: 1200px;
  --container-narrow: 800px;
  --nav-height: 70px;
  --section-padding: 6rem;
}