/* ============================================
   BASE.CSS — Futuristic Design System
   Dr. Soon Yee Wong Researcher Profile
   Inspired by Open Design's clean aesthetic
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=JetBrains+Mono:wght@400;500;600&display=swap');

:root {
  /* Light Mode */
  --bg-primary: #fafafa;
  --bg-secondary: #f0f0f0;
  --bg-card: #ffffff;
  --bg-elevated: #ffffff;
  --text-primary: #0a0a0a;
  --text-secondary: #525252;
  --text-muted: #a3a3a3;
  --border: #e5e5e5;
  --border-subtle: #f0f0f0;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-glow: rgba(99, 102, 241, 0.15);
  --accent-subtle: rgba(99, 102, 241, 0.08);
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --gradient-hero: linear-gradient(135deg, #0a0a0a 0%, #1a1a2e 50%, #16213e 100%);
  --gradient-card: linear-gradient(145deg, rgba(255,255,255,0.9) 0%, rgba(245,245,245,0.9) 100%);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.06);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.08);
  --shadow-glow: 0 0 30px rgba(99, 102, 241, 0.1);
  --glass: rgba(255,255,255,0.7);
  --glass-border: rgba(255,255,255,0.3);

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Spacing */
  --max-width: 1200px;
  --section-padding: 5rem 1.5rem;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-fast: 150ms var(--ease-out);
  --transition-base: 300ms var(--ease-out);
  --transition-slow: 500ms var(--ease-out);
}

[data-theme="dark"] {
  --bg-primary: #0a0a0a;
  --bg-secondary: #141414;
  --bg-card: #1a1a1a;
  --bg-elevated: #222222;
  --text-primary: #fafafa;
  --text-secondary: #a3a3a3;
  --text-muted: #525252;
  --border: #262626;
  --border-subtle: #1f1f1f;
  --accent: #818cf8;
  --accent-hover: #6366f1;
  --accent-glow: rgba(129, 140, 248, 0.2);
  --accent-subtle: rgba(129, 140, 248, 0.08);
  --gradient-hero: linear-gradient(135deg, #0a0a0a 0%, #0f0f1a 50%, #0a1628 100%);
  --gradient-card: linear-gradient(145deg, rgba(26,26,26,0.9) 0%, rgba(20,20,20,0.9) 100%);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 40px rgba(129, 140, 248, 0.15);
  --glass: rgba(20,20,20,0.8);
  --glass-border: rgba(255,255,255,0.08);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  transition: background-color var(--transition-base), color var(--transition-base);
}

/* Selection */
::selection { background: var(--accent); color: white; }

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

/* Scrollbar */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--text-muted); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-secondary); }

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.5rem, 5vw, 4rem); font-weight: 800; }
h2 { font-size: clamp(1.75rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 2vw, 1.5rem); }
h4 { font-size: 1.125rem; }

p { color: var(--text-secondary); line-height: 1.7; margin-bottom: 1rem; }
strong { color: var(--text-primary); font-weight: 600; }
em { font-style: italic; }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition-fast);
}
a:hover { color: var(--accent-hover); }

img { max-width: 100%; height: auto; display: block; }

ul, ol { padding-left: 1.5rem; margin-bottom: 1rem; }
li { margin-bottom: 0.35rem; color: var(--text-secondary); }

/* Container */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }
.container-narrow { max-width: 800px; }

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

/* Section */
section { padding: var(--section-padding); position: relative; }

.section-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  margin-bottom: 2rem;
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 40px;
  height: 3px;
  background: var(--accent);
  margin-top: 0.75rem;
  border-radius: 2px;
  transition: width var(--transition-base);
}

.section-title:hover::after { width: 80px; }
.text-center .section-title::after { margin-left: auto; margin-right: auto; }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  font-family: var(--font-sans);
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.2) 0%, transparent 50%);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn:hover::before { opacity: 1; }

.btn-primary {
  background: var(--accent);
  color: white;
  box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px var(--accent-glow);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1.5px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-subtle);
}

.btn-sm { padding: 0.5rem 1.25rem; font-size: 0.8125rem; }

/* Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.75rem;
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  border-radius: var(--radius-full);
  background: var(--accent-subtle);
  color: var(--accent);
}

/* Animations */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-30px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(30px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.9); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@keyframes glow {
  0%, 100% { box-shadow: 0 0 20px var(--accent-glow); }
  50% { box-shadow: 0 0 40px var(--accent-glow); }
}

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.animate-fade-in-up { animation: fadeInUp 0.6s var(--ease-out) forwards; opacity: 0; }
.animate-fade-in { animation: fadeIn 0.6s var(--ease-out) forwards; opacity: 0; }
.animate-slide-left { animation: slideInLeft 0.6s var(--ease-out) forwards; opacity: 0; }
.animate-slide-right { animation: slideInRight 0.6s var(--ease-out) forwards; opacity: 0; }
.animate-scale { animation: scaleIn 0.5s var(--ease-out) forwards; opacity: 0; }

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }