@import url('https://fonts.googleapis.com/css2?family=Inter:ital,wght@0,300..600;1,300..600&family=Outfit:wght@300..800&display=swap');

/* ==========================================================================
   1. Design System Tokens (Tiers 1, 2, 3)
   ========================================================================== */
:root {
  /* --- Tier 1: Literal Tokens --- */
  /* Fonts */
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-heading: 'Outfit', var(--font-sans);

  /* Literal Colors (HSL) */
  --color-slate-50: 210 40% 98%;
  --color-slate-100: 210 40% 96.1%;
  --color-slate-200: 214 32% 91%;
  --color-slate-300: 213 27% 84%;
  --color-slate-700: 215 25% 27%;
  --color-slate-800: 217 33% 17%;
  --color-slate-900: 222 47% 11%;
  --color-slate-950: 222 47% 6%;

  --color-sage-50: 120 15% 95%;
  --color-sage-100: 120 15% 90%;
  --color-sage-200: 120 14% 80%;
  --color-sage-600: 120 12% 40%;
  --color-sage-700: 120 13% 30%;
  --color-sage-800: 120 15% 20%;
  --color-sage-900: 120 18% 12%;

  --color-gold-100: 45 60% 95%;
  --color-gold-400: 43 75% 58%;
  --color-gold-500: 42 78% 50%;
  --color-gold-600: 40 82% 40%;
  
  --color-blush-100: 12 70% 96%;
  --color-blush-400: 12 60% 80%;
  --color-blush-600: 12 50% 60%;

  /* Spacing (using rem) */
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4.5rem;

  /* Shadows (layered for premium depth) */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -4px rgba(0, 0, 0, 0.05), 0 0 1px 0 rgba(0, 0, 0, 0.1);
  --shadow-premium: 0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.08);

  /* Animation */
  --transition-speed: 0.3s;
  --ease-premium: cubic-bezier(0.16, 1, 0.3, 1);

  /* --- Tier 2: Semantic Tokens & Adaptive Themes --- */
  /* Enable automatic browser theme adjustments */
  color-scheme: light dark;

  /* Resolve dynamic colors using light-dark() */
  --color-bg-base: light-dark(hsl(var(--color-slate-50)), hsl(var(--color-slate-950)));
  --color-bg-surface: light-dark(hsl(0 0% 100%), hsl(var(--color-slate-900)));
  --color-bg-surface-subtle: light-dark(hsl(var(--color-slate-100)), hsl(var(--color-slate-800)));
  
  --color-text-main: light-dark(hsl(var(--color-slate-800)), hsl(var(--color-slate-50)));
  --color-text-muted: light-dark(hsl(var(--color-slate-700) / 0.75), hsl(var(--color-slate-200) / 0.7));
  --color-text-inverse: light-dark(hsl(var(--color-slate-50)), hsl(var(--color-slate-900)));

  --color-accent: light-dark(hsl(var(--color-sage-700)), hsl(var(--color-sage-200)));
  --color-accent-subtle: light-dark(hsl(var(--color-sage-50)), hsl(var(--color-sage-900)));
  --color-primary: light-dark(hsl(var(--color-slate-900)), hsl(0 0% 100%));

  --color-border: light-dark(hsl(var(--color-slate-200)), hsl(var(--color-slate-800)));
  --color-border-hover: light-dark(hsl(var(--color-slate-300)), hsl(var(--color-slate-700)));

  /* Glassmorphism settings */
  --glass-bg: light-dark(rgba(255, 255, 255, 0.65), rgba(15, 23, 42, 0.5));
  --glass-border: light-dark(rgba(226, 232, 240, 0.8), rgba(30, 41, 59, 0.5));
  --glass-backdrop-filter: blur(12px) saturate(190%);
}

/* ==========================================================================
   2. Modern CSS Reset (No global '*' resets)
   ========================================================================== */
html {
  box-sizing: border-box;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

*, *::before, *::after {
  box-sizing: inherit;
}

body {
  margin: 0;
  min-block-size: 100vh;
  min-block-size: 100dvh;
  background-color: var(--color-bg-base);
  color: var(--color-text-main);
  text-rendering: optimizeSpeed;
  transition: background-color var(--transition-speed) var(--ease-premium), color var(--transition-speed) var(--ease-premium);
  overflow-x: hidden;
}

h1, h2, h3, h4, p, figure, blockquote, dl, dd {
  margin-block-start: 0;
  margin-block-end: 0;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  color: var(--color-primary);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

ul, ol {
  margin-block-start: 0;
  margin-block-end: 0;
  padding-inline-start: 0;
  list-style: none;
}

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

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

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

/* ==========================================================================
   3. Interactivity & Focus Management
   ========================================================================== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 4px;
}

button, .btn {
  cursor: pointer;
  touch-action: manipulation;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  min-block-size: 44px; /* Accessible touch target */
  min-inline-size: 44px;
  padding: var(--space-sm) var(--space-lg);
  border: 1px solid transparent;
  border-radius: 9999px;
  background-color: var(--color-primary);
  color: var(--color-bg-base);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  transition: 
    background-color var(--transition-speed) var(--ease-premium),
    transform 0.15s var(--ease-premium),
    box-shadow var(--transition-speed) var(--ease-premium);
}

button:hover:not(:disabled), .btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

button:active:not(:disabled), .btn:active {
  transform: translateY(0);
}

button:disabled, .btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Secondary Button variant */
.btn-secondary {
  background-color: var(--color-bg-surface-subtle);
  border-color: var(--color-border);
  color: var(--color-text-main);
}
.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-bg-surface);
  border-color: var(--color-border-hover);
}

/* High Contrast Mode fallback */
@media (forced-colors: active) {
  :focus-visible {
    outline: 2px solid ButtonText;
  }
  button, .btn {
    border: 1px solid ButtonText;
    background-color: ButtonFace;
    color: ButtonText;
  }
}

/* ==========================================================================
   4. Layout Utilities
   ========================================================================== */
.container {
  inline-size: 90%;
  max-inline-size: 1200px;
  margin-inline: auto;
}

.section-padding {
  padding-block: clamp(var(--space-2xl), 6vw, var(--space-3xl));
}

/* Grid & Flex Utilities */
.grid {
  display: grid;
  gap: var(--space-lg);
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Header & Navigation */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--glass-bg);
  backdrop-filter: var(--glass-backdrop-filter);
  -webkit-backdrop-filter: var(--glass-backdrop-filter);
  border-block-end: 1px solid var(--glass-border);
  transition: background var(--transition-speed) var(--ease-premium), border-color var(--transition-speed) var(--ease-premium);
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  block-size: 70px;
}

.logo {
  font-family: var(--font-heading);
  font-size: 1.4rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-menu {
  display: flex;
  gap: var(--space-xl);
}

.nav-link {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  position: relative;
  padding-block: var(--space-xs);
  transition: color var(--transition-speed) var(--ease-premium);
}

.nav-link:hover, .nav-link.active {
  color: var(--color-primary);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--transition-speed) var(--ease-premium);
}

.nav-link:hover::after, .nav-link.active::after {
  transform: scaleX(1);
  transform-origin: left;
}

/* Theme Switcher */
.theme-toggle-btn {
  background: none;
  border: none;
  color: var(--color-text-main);
  padding: var(--space-xs);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-block-size: 40px;
  min-inline-size: 40px;
  transition: background-color var(--transition-speed) var(--ease-premium), transform 0.2s;
}

.theme-toggle-btn:hover {
  background-color: var(--color-bg-surface-subtle);
  transform: rotate(15deg);
  box-shadow: none;
}

.theme-toggle-btn svg {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Mobile Nav Toggles */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--color-text-main);
  padding: var(--space-xs);
  min-block-size: 40px;
  min-inline-size: 40px;
}

@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: block;
  }
  .nav-menu {
    position: absolute;
    top: 71px;
    left: 0;
    width: 100%;
    background-color: var(--color-bg-surface);
    border-block-end: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--space-xl);
    gap: var(--space-lg);
    display: none; /* Toggled by class */
    box-shadow: var(--shadow-lg);
  }
  .nav-menu.open {
    display: flex;
  }
}

/* Footer styling */
footer {
  background-color: var(--color-bg-surface-subtle);
  border-block-start: 1px solid var(--color-border);
  padding-block: var(--space-2xl);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

.footer-logo {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 1.2rem;
  margin-block-end: var(--space-sm);
  color: var(--color-primary);
}

/* Accessibility: Reduced motion settings */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}