/* ============================================================
   BASE.CSS — Shared Foundation
   Reset, layout grid, transitions, responsive breakpoints
   ============================================================ */

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

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

body {
  min-height: 100vh;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  line-height: 1.5;
}

/* --- Theme Transition --- */
html.theme-transitioning,
html.theme-transitioning *,
html.theme-transitioning *::before,
html.theme-transitioning *::after {
  transition:
    background-color 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    color 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    border-color 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    box-shadow 0.5s cubic-bezier(0.4, 0, 0.2, 1),
    opacity 0.5s cubic-bezier(0.4, 0, 0.2, 1) !important;
}

/* --- Default CSS Custom Properties (overridden by theme files) --- */
:root {
  /* Colors */
  --bg: #f8f9fa;
  --surface: #f8f9fa;
  --surface-container-low: #f1f4f6;
  --surface-container-high: #e3e9ec;
  --primary: #5d5e61;
  --primary-dim: #515255;
  --on-surface: #2b3437;
  --on-surface-variant: #586064;
  --on-primary: #f7f7fa;
  --accent: #15696d;
  --accent-secondary: #cfe6f2;
  --outline-variant: #abb3b7;
  --outline: #737c7f;

  /* Typography */
  --font-headline: 'Space Grotesk', sans-serif;
  --font-body: 'Work Sans', sans-serif;
  --font-label: 'Space Grotesk', sans-serif;
  --font-signature: 'Nanum Pen Script', cursive;

  /* Shape */
  --radius: 0px;

  /* Spacing */
  --header-px: clamp(1.5rem, 5vw, 5.5rem);
  --header-py: 1.4rem;
  --content-px: clamp(1.5rem, 5vw, 5.5rem);

  /* Decorative */
  --texture-opacity: 0;
  --grain-opacity: 0;
  --glow-opacity: 0;
}

/* --- Selection --- */
::selection {
  background: var(--accent-secondary);
  color: var(--on-surface);
}

/* --- Layout --- */

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--header-py) var(--header-px);
  background: var(--bg);
  font-family: var(--font-label);
}

.site-title {
  font-family: var(--font-headline);
  font-size: clamp(1.125rem, 2.5vw, 1.5rem);
  font-weight: 700;
  color: var(--on-surface);
  letter-spacing: -0.02em;
  line-height: 1.2;
}

/* Theme Selector */
.theme-selector-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.theme-selector-label {
  font-family: var(--font-label);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--on-surface-variant);
  font-weight: 500;
}

.theme-selector {
  font-family: var(--font-label);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--on-surface);
  background: var(--surface-container-low);
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0.5rem 2rem 0.5rem 0.75rem;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  outline: none;
  letter-spacing: 0.02em;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%23586064' viewBox='0 0 16 16'%3E%3Cpath d='M4.646 6.646a.5.5 0 0 1 .708 0L8 9.293l2.646-2.647a.5.5 0 1 1 .708.708l-3 3a.5.5 0 0 1-.708 0l-3-3a.5.5 0 0 1 0-.708z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.5rem center;
  background-size: 1rem;
}

.theme-selector:hover {
  border-color: var(--outline-variant);
}

.theme-selector:focus-visible {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--accent-secondary);
}

/* Main Content */
.site-main {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--content-px);
  padding-top: calc(var(--header-py) * 2 + 3rem);
  min-height: 100vh;
  min-height: 100dvh;
  position: relative;
}

.content-container {
  width: 100%;
  max-width: 64rem;
  text-align: center;
  position: relative;
  z-index: 10;
}

/* Decorative label above quote */
.content-label {
  display: block;
  font-family: var(--font-label);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.25em;
  color: var(--on-surface-variant);
  opacity: 0.6;
  margin-bottom: 2rem;
}

/* Main quote */
.content-quote {
  font-family: var(--font-headline);
  font-size: clamp(2rem, 6vw, 4.5rem);
  font-weight: 300;
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--on-surface);
  max-width: 52rem;
  margin: 0 auto;
}

/* Footer annotation */
.content-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin-top: 3rem;
}

.content-footer-line {
  width: 3rem;
  height: 1px;
  background: var(--outline-variant);
  opacity: 0.3;
}

.content-footer-text {
  font-family: var(--font-label);
  font-size: 0.625rem;
  text-transform: uppercase;
  letter-spacing: 0.3em;
  color: var(--outline);
}

/* Site Footer */
.site-footer {
  padding: 2rem var(--header-px);
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  z-index: 10;
}

.footer-text {
  font-family: var(--font-label);
  font-size: 0.625rem;
  text-transform: uppercase;
  letter-spacing: 0.4em;
  color: var(--outline-variant);
}

/* --- Background Layers --- */

/* Texture overlay (grid, dots, grain) — controlled per theme */
.bg-texture {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: var(--texture-opacity);
}

/* Decorative glow blobs */
.bg-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
  opacity: var(--glow-opacity);
}

.bg-glow-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(120px);
}

.bg-glow-blob--primary {
  top: 20%;
  right: 10%;
  width: 24rem;
  height: 24rem;
  background: var(--primary);
  opacity: 0.08;
}

.bg-glow-blob--accent {
  bottom: 20%;
  left: 10%;
  width: 16rem;
  height: 16rem;
  background: var(--accent-secondary);
  opacity: 0.12;
}

/* Grain overlay */
.bg-grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: var(--grain-opacity);
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
}

/* --- Responsive --- */

@media (max-width: 768px) {
  .site-header {
    padding: 1rem 1.25rem;
  }

  .site-main {
    padding: 1.25rem;
    padding-top: 5rem;
  }

  .content-quote {
    font-size: clamp(1.75rem, 8vw, 2.5rem);
  }

  .theme-selector-label {
    display: none;
  }

  .site-footer {
    padding: 1.5rem 1.25rem;
  }
}

@media (max-width: 480px) {
  .content-label {
    font-size: 0.5625rem;
  }

  .content-footer {
    flex-direction: column;
    gap: 0.5rem;
  }

  .content-footer-line {
    display: none;
  }
}

/* --- Accessibility --- */
@media (prefers-reduced-motion: reduce) {
  html.theme-transitioning,
  html.theme-transitioning *,
  html.theme-transitioning *::before,
  html.theme-transitioning *::after {
    transition: none !important;
  }
}

/* Screen reader only */
.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;
}