/* ============================================================
   MEDLIFE OVERSEAS — Premium Design System v2
   Inspired by top Dribbble/Behance medical education UIs
   ============================================================ */

/* ── CSS Custom Properties (Design Tokens) ─────────────────── */
:root {
  /* Primary — Deep Navy to Sapphire Blue */
  --color-primary-900: #080E1E;
  --color-primary-800: #0C1630;
  --color-primary-700: #132044;
  --color-primary-600: #1A3366;
  --color-primary-500: #2563EB;
  --color-primary-400: #4B83F2;
  --color-primary-300: #7BA6F7;
  --color-primary-200: #B4CDFA;
  --color-primary-100: #E0EBFE;
  --color-primary-50:  #F0F5FF;

  /* Neutrals — Warmer tones */
  --color-white: #FFFFFF;
  --color-gray-50:  #F7F8FA;
  --color-gray-100: #EEF0F4;
  --color-gray-200: #DDE1E9;
  --color-gray-300: #BFC5D2;
  --color-gray-400: #8B95A8;
  --color-gray-500: #5F6B82;
  --color-gray-600: #434D60;
  --color-gray-700: #2E3545;
  --color-gray-800: #1A1F2E;
  --color-gray-900: #0D1117;

  /* Accent — Success Emerald */
  --color-accent-500: #10B981;
  --color-accent-400: #34D399;
  --color-accent-300: #6EE7B7;
  --color-accent-100: #D1FAE5;

  /* Warm Accent — Gold for premium feel */
  --color-gold-500: #D4A843;
  --color-gold-400: #E5C06A;
  --color-gold-300: #F0D890;
  --color-gold-100: #FBF3DC;

  /* Warning */
  --color-warning-500: #F59E0B;
  --color-warning-100: #FEF3C7;

  /* Error */
  --color-error-500: #EF4444;
  --color-error-100: #FEE2E2;

  /* Gradients — Richer, more dramatic */
  --gradient-hero: linear-gradient(145deg, #060B18 0%, #0C1630 25%, #132044 55%, #1A3366 80%, #1E3D7A 100%);
  --gradient-hero-radial: radial-gradient(ellipse at 70% 20%, rgba(37, 99, 235, 0.25) 0%, transparent 60%);
  --gradient-cta: linear-gradient(135deg, #2563EB 0%, #4B83F2 50%, #2563EB 100%);
  --gradient-cta-hover: linear-gradient(135deg, #1D4ED8 0%, #3B75E8 50%, #1D4ED8 100%);
  --gradient-dark-section: linear-gradient(180deg, #080E1E 0%, #0C1630 50%, #101B38 100%);
  --gradient-card-shine: linear-gradient(135deg, rgba(255,255,255,0.12) 0%, rgba(255,255,255,0) 50%);
  --gradient-glass: linear-gradient(135deg, rgba(255,255,255,0.06) 0%, rgba(255,255,255,0.02) 100%);
  --gradient-mesh: radial-gradient(at 80% 10%, rgba(75,131,242,.15) 0, transparent 50%),
                   radial-gradient(at 20% 80%, rgba(16,185,129,.08) 0, transparent 50%),
                   radial-gradient(at 50% 50%, rgba(212,168,67,.06) 0, transparent 50%);
  --gradient-warm-accent: linear-gradient(135deg, #D4A843 0%, #E5C06A 100%);
  --gradient-section-divider: linear-gradient(90deg, transparent 0%, var(--color-gray-200) 50%, transparent 100%);

  /* Shadows — Richer with colored undertones */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.06), 0 2px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.08), 0 4px 12px rgba(0,0,0,0.04);
  --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.12), 0 8px 20px rgba(0,0,0,0.06);
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.04), 0 1px 3px rgba(0,0,0,0.02);
  --shadow-card-hover: 0 20px 50px rgba(0, 0, 0, 0.10), 0 8px 20px rgba(0,0,0,0.06);
  --shadow-glow: 0 0 40px rgba(37, 99, 235, 0.30), 0 0 80px rgba(37, 99, 235, 0.10);
  --shadow-glow-sm: 0 0 20px rgba(37, 99, 235, 0.20);
  --shadow-glow-gold: 0 0 30px rgba(212, 168, 67, 0.2);
  --shadow-inner-glow: inset 0 1px 0 rgba(255,255,255,0.05);

  /* Typography */
  --font-heading: 'Inter', system-ui, -apple-system, sans-serif;
  --font-body: 'Noto Sans', system-ui, -apple-system, sans-serif;

  /* Spacing Scale */
  --space-xs: 0.25rem;   /* 4px */
  --space-sm: 0.5rem;    /* 8px */
  --space-md: 1rem;      /* 16px */
  --space-lg: 1.5rem;    /* 24px */
  --space-xl: 2rem;      /* 32px */
  --space-2xl: 3rem;     /* 48px */
  --space-3xl: 4rem;     /* 64px */
  --space-4xl: 6rem;     /* 96px */
  --space-5xl: 8rem;     /* 128px */

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --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);
  --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
  --duration-fast: 150ms;
  --duration-normal: 300ms;
  --duration-slow: 500ms;
  --duration-slower: 700ms;

  /* Layout */
  --container-max: 1280px;
  --container-narrow: 900px;
  --nav-height: 88px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--color-gray-700);
  background-color: var(--color-white);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--color-gray-900);
  line-height: 1.15;
  font-weight: 700;
}

a {
  color: var(--color-primary-500);
  text-decoration: none;
  transition: color var(--duration-fast) var(--ease-smooth);
}

a:hover {
  color: var(--color-primary-600);
}

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

ul, ol {
  list-style: none;
}

button {
  font-family: var(--font-body);
  cursor: pointer;
  border: none;
  background: none;
  font-size: inherit;
}

input, textarea, select {
  font-family: var(--font-body);
  font-size: 1rem;
}

/* ── Layout Utilities ──────────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding: var(--space-4xl) 0;
  position: relative;
}

.section--dark {
  background: var(--gradient-dark-section);
  color: var(--color-white);
}

.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--color-white);
}

.section--gray {
  background-color: var(--color-gray-50);
}

.section--blue-tint {
  background: linear-gradient(180deg, var(--color-primary-50) 0%, var(--color-white) 100%);
}

/* ── Typography Utilities ──────────────────────────────────── */
.h-display {
  font-family: var(--font-heading);
  font-size: clamp(2.75rem, 5vw, 4.5rem);
  font-weight: 800;
  line-height: 1.06;
  letter-spacing: -0.035em;
}

.h1 {
  font-size: clamp(2.25rem, 4vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.025em;
}

.h2 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.015em;
}

.h3 {
  font-size: clamp(1.25rem, 2vw, 1.5rem);
  font-weight: 600;
}

.h4 {
  font-size: clamp(1rem, 1.5vw, 1.25rem);
  font-weight: 600;
}

.body-lg {
  font-size: 1.125rem;
  line-height: 1.75;
}

.body-sm {
  font-size: 0.875rem;
  line-height: 1.6;
}

.overline {
  font-family: var(--font-heading);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-primary-400);
}

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

/* ── Button System ─────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.875rem 2rem;
  font-family: var(--font-heading);
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1;
  border-radius: var(--radius-md);
  transition: all var(--duration-normal) var(--ease-out);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
  letter-spacing: 0.01em;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.15) 0%, rgba(255,255,255,0) 60%);
  opacity: 0;
  transition: opacity var(--duration-normal) var(--ease-smooth);
}

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

.btn--primary {
  background: var(--gradient-cta);
  color: var(--color-white);
  box-shadow: 0 4px 15px rgba(37,99,235,0.25), var(--shadow-inner-glow);
  border: 1px solid rgba(255,255,255,0.1);
}

.btn--primary:hover {
  background: var(--gradient-cta-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-3px);
  color: var(--color-white);
}

.btn--primary:active {
  transform: translateY(-1px);
}

.btn--secondary {
  background: var(--color-white);
  color: var(--color-primary-600);
  border: 1.5px solid var(--color-primary-200);
  box-shadow: var(--shadow-sm);
}

.btn--secondary:hover {
  background: var(--color-primary-50);
  border-color: var(--color-primary-400);
  transform: translateY(-3px);
  color: var(--color-primary-700);
  box-shadow: var(--shadow-md);
}

.btn--ghost {
  background: rgba(255, 255, 255, 0.06);
  color: var(--color-white);
  border: 1.5px solid rgba(255, 255, 255, 0.18);
  backdrop-filter: blur(8px);
}

.btn--ghost:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: rgba(255, 255, 255, 0.35);
  transform: translateY(-3px);
  color: var(--color-white);
}

.btn--sm {
  padding: 0.625rem 1.25rem;
  font-size: 0.8125rem;
  border-radius: var(--radius-sm);
}

.btn--lg {
  padding: 1.125rem 2.5rem;
  font-size: 1rem;
  border-radius: var(--radius-md);
}

.btn--icon {
  padding: 0.75rem;
  border-radius: var(--radius-md);
}

/* ── Selection ─────────────────────────────────────────────── */
::selection {
  background: var(--color-primary-200);
  color: var(--color-primary-900);
}

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

::-webkit-scrollbar-track {
  background: var(--color-gray-50);
}

::-webkit-scrollbar-thumb {
  background: var(--color-gray-300);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-gray-400);
}

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 768px) {
  .section {
    padding: var(--space-3xl) 0;
  }

  .container {
    padding: 0 var(--space-md);
  }
}

@media (max-width: 480px) {
  .section {
    padding: var(--space-2xl) 0;
  }
}

/* ── Mobile Touch Fixes ───────────────────────────────────── */
/* Disable blue tap highlight on all interactive elements */
a, button, input, select, textarea, [role="button"] {
  -webkit-tap-highlight-color: transparent;
}

/* Prevent text selection on navigation elements */
.navbar, .navbar__link, .navbar__dropdown-item, .navbar__cta,
.navbar__hamburger, .btn {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}

/* Body scroll lock when mobile nav is open */
body.nav-open {
  overflow: hidden;
  touch-action: none;
}