/* ============================================
   Direct Research Korea — Design System
   Monochrome: White, Black, Gray
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  /* White */
  --color-white: #FFFFFF;
  --color-white-warm: #FAFAFA;
  --color-offwhite: #F5F5F5;
  --color-cream: #EEEEEE;

  /* Black */
  --color-black: #111111;
  --color-charcoal: #1A1A1A;
  --color-dark: #2A2A2A;

  /* Gray Scale */
  --color-gray-100: #F0F0F0;
  --color-gray-200: #E2E2E2;
  --color-gray-300: #C8C8C8;
  --color-gray-400: #999999;
  --color-gray-500: #777777;
  --color-gray-600: #555555;
  --color-gray-700: #444444;
  --color-gray-800: #333333;
  --color-gray-900: #222222;

  /* Accent = Dark charcoal / Black */
  --color-accent: #222222;
  --color-accent-light: #444444;
  --color-accent-dark: #111111;
  --color-accent-glow: rgba(0, 0, 0, 0.04);
  --color-accent-hover: rgba(0, 0, 0, 0.07);

  /* Semantic */
  --color-text-primary: var(--color-black);
  --color-text-secondary: var(--color-gray-600);
  --color-text-muted: var(--color-gray-400);
  --color-text-accent: var(--color-accent);
  --color-bg-primary: var(--color-white);
  --color-bg-secondary: var(--color-offwhite);
  --color-bg-surface: var(--color-white);
  --color-border: rgba(0, 0, 0, 0.08);
  --color-border-hover: rgba(0, 0, 0, 0.2);

  /* Gradients — Monochrome */
  --gradient-hero: linear-gradient(180deg, #FFFFFF 0%, #F5F5F5 100%);
  --gradient-accent: linear-gradient(135deg, #222222 0%, #444444 50%, #222222 100%);
  --gradient-card: linear-gradient(180deg, #FFFFFF 0%, #FAFAFA 100%);

  /* Typography */
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;

  --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;
  --text-6xl: 3.75rem; --text-7xl: 4.5rem;

  --leading-tight: 1.15; --leading-snug: 1.3;
  --leading-normal: 1.6; --leading-relaxed: 1.75;

  --tracking-tight: -0.02em; --tracking-normal: 0;
  --tracking-wide: 0.05em; --tracking-wider: 0.1em;

  /* 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;
  --space-32: 8rem;

  /* Layout */
  --container-sm: 640px; --container-md: 768px;
  --container-lg: 1024px; --container-xl: 1200px; --container-2xl: 1400px;

  /* Borders */
  --radius-sm: 4px; --radius-md: 8px; --radius-lg: 12px;
  --radius-xl: 16px; --radius-2xl: 24px; --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.1);
  --shadow-xl: 0 20px 60px rgba(0,0,0,0.12);
  --shadow-accent: 0 4px 20px rgba(0,0,0,0.12);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4,0,0.2,1);
  --transition-normal: 300ms cubic-bezier(0.4,0,0.2,1);
  --transition-slow: 500ms cubic-bezier(0.4,0,0.2,1);
  --transition-spring: 500ms cubic-bezier(0.34,1.56,0.64,1);

  /* Z-index */
  --z-base: 1; --z-dropdown: 100; --z-sticky: 200;
  --z-overlay: 300; --z-modal: 400; --z-toast: 500;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  overflow-x: hidden;
}

img { max-width:100%; height:auto; display:block; }
a { color:inherit; text-decoration:none; transition:color var(--transition-fast); }
a:hover { color: var(--color-gray-500); }
ul,ol { list-style:none; }
button { font-family:inherit; cursor:pointer; border:none; background:none; }

/* Typography */
.heading-1 { font-family:var(--font-heading); font-size:var(--text-6xl); font-weight:700; line-height:var(--leading-tight); letter-spacing:var(--tracking-tight); color:var(--color-black); }
.heading-2 { font-family:var(--font-heading); font-size:var(--text-4xl); font-weight:700; line-height:var(--leading-tight); letter-spacing:var(--tracking-tight); color:var(--color-black); }
.heading-3 { font-family:var(--font-heading); font-size:var(--text-2xl); font-weight:600; line-height:var(--leading-snug); color:var(--color-black); }
.heading-4 { font-family:var(--font-heading); font-size:var(--text-xl); font-weight:600; line-height:var(--leading-snug); color:var(--color-black); }
.body-lg { font-size:var(--text-lg); line-height:var(--leading-relaxed); color:var(--color-text-secondary); }
.body-base { font-size:var(--text-base); line-height:var(--leading-normal); color:var(--color-text-secondary); }
.body-sm { font-size:var(--text-sm); line-height:var(--leading-normal); color:var(--color-text-muted); }
.label { font-family:var(--font-heading); font-size:var(--text-xs); font-weight:600; letter-spacing:var(--tracking-wider); text-transform:uppercase; color:var(--color-gray-500); }

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

/* Layout */
.container { width:100%; max-width:var(--container-xl); margin:0 auto; padding:0 var(--space-6); }
.container--narrow { max-width:var(--container-lg); }
.container--wide { max-width:var(--container-2xl); }
.section { padding:var(--space-24) 0; }
.section--sm { padding:var(--space-16) 0; }
.grid { display:grid; gap:var(--space-8); }
.grid--2 { grid-template-columns:repeat(2,1fr); }
.grid--3 { grid-template-columns:repeat(3,1fr); }
.grid--4 { grid-template-columns:repeat(4,1fr); }

/* Reveal */
.reveal { opacity:0; transform:translateY(30px); transition:opacity 0.8s cubic-bezier(0.16,1,0.3,1),transform 0.8s cubic-bezier(0.16,1,0.3,1); }
.reveal.visible { 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; }

/* Responsive */
@media (max-width:1024px) {
  :root { --text-6xl:2.75rem; --text-5xl:2.25rem; --text-4xl:1.875rem; }
  .grid--3,.grid--4 { grid-template-columns:repeat(2,1fr); }
  .section { padding:var(--space-16) 0; }
}
@media (max-width:768px) {
  :root { --text-6xl:2.25rem; --text-5xl:1.875rem; --text-4xl:1.5rem; --text-3xl:1.375rem; }
  .container { padding:0 var(--space-4); }
  .grid--2,.grid--3,.grid--4 { grid-template-columns:1fr; }
  .section { padding:var(--space-12) 0; }
}

::selection { background:var(--color-black); color:var(--color-white); }
::-webkit-scrollbar { width:8px; }
::-webkit-scrollbar-track { background:var(--color-offwhite); }
::-webkit-scrollbar-thumb { background:var(--color-gray-300); border-radius:var(--radius-full); }
::-webkit-scrollbar-thumb:hover { background:var(--color-gray-500); }