/* ========================================
   DATABASE HISTORY - SCROLLYTELLING STYLES
   ======================================== */

/* CSS Custom Properties (Design Tokens) */
:root {
  /* Era Color Palettes */
  --punch-primary: #8b4513;
  --punch-secondary: #d2691e;
  --punch-bg: #2d1810;

  --tape-primary: #2f4f4f;
  --tape-secondary: #708090;
  --tape-bg: #1a2a2a;

  --hdd-primary: #1a1a2e;
  --hdd-secondary: #4a4a6a;
  --hdd-bg: #0f0f1a;

  --ssd-primary: #0f3460;
  --ssd-secondary: #16213e;
  --ssd-bg: #0a1628;

  --cloud-primary: #e8f4f8;
  --cloud-secondary: #b8d4e3;
  --cloud-bg: #1a2d3d;

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

  /* Spacing */
  --section-padding: 100vh;
  --content-max-width: 1200px;

  /* Transitions */
  --transition-smooth: 0.3s ease-out;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  background: #0a0a0f;
  color: #e0e0e0;
  line-height: 1.6;
  overflow-x: hidden;
}

/* ========================================
   HERO SECTION
   ======================================== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  /* Dark at top, blending to punch-bg at bottom to match first section */
  background: linear-gradient(
    180deg,
    #0a0a0f 0%,
    #0a0a0f 50%,
    var(--punch-bg) 100%
  );
  text-align: center;
  padding: 2rem;
}

.hero-content {
  max-width: 600px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #fff 0%, #a0a0a0 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-size: 1.1rem;
  color: #888;
  margin-bottom: 1rem;
}

.hero .author {
  font-size: 0.95rem;
  color: #666;
  font-style: italic;
  margin-bottom: 2.5rem;
}

.scroll-indicator {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: #666;
  font-size: 0.9rem;
  animation: bounce 2s infinite;
}

.arrow-down {
  width: 20px;
  height: 20px;
  border-right: 2px solid #666;
  border-bottom: 2px solid #666;
  transform: rotate(45deg);
}

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

/* ========================================
   STRATA SECTIONS
   ======================================== */
.scrolly-container {
  position: relative;
}

.strata {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 4rem 2rem;
  position: relative;
  transition: background var(--transition-smooth);
}

/* Era-specific backgrounds
   Each section: own color throughout, blending to NEXT section at bottom only.
   The previous section's bottom already matches our top. */

.strata-punch {
  /* Punch brown throughout, blending to tape slate at bottom */
  background: linear-gradient(
    180deg,
    var(--punch-bg) 0%,
    var(--punch-bg) 80%,
    var(--tape-bg) 100%
  );
}

.strata-tape {
  /* Tape slate throughout, blending to hdd navy at bottom */
  background: linear-gradient(
    180deg,
    var(--tape-bg) 0%,
    var(--tape-bg) 80%,
    var(--hdd-bg) 100%
  );
}

.strata-hdd {
  /* HDD navy throughout, blending to ssd blue at bottom */
  background: linear-gradient(
    180deg,
    var(--hdd-bg) 0%,
    var(--hdd-bg) 80%,
    var(--ssd-bg) 100%
  );
}

.strata-ssd {
  /* SSD blue throughout, blending to cloud teal at bottom */
  background: linear-gradient(
    180deg,
    var(--ssd-bg) 0%,
    var(--ssd-bg) 80%,
    var(--cloud-bg) 100%
  );
}

.strata-cloud {
  /* Cloud teal throughout, blending to footer dark at bottom */
  background: linear-gradient(
    180deg,
    var(--cloud-bg) 0%,
    var(--cloud-bg) 80%,
    #0a0a0f 100%
  );
}

/* Strata Content Layout */
.strata-content {
  display: flex;
  gap: 2rem;
  max-width: var(--content-max-width);
  margin: 0 auto 2rem;
  width: 100%;
}

/* Visualization Container */
.visualization-container {
  flex: 1;
  min-height: 400px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

/* SVG placeholder text */
.visualization-container::before {
  content: "Animation Loading...";
  color: rgba(255, 255, 255, 0.2);
  font-size: 0.9rem;
}

.visualization-container:has(svg)::before {
  display: none;
}

/* ========================================
   LIBRARY METAPHOR SIDEBAR
   ======================================== */
.library-metaphor {
  width: 200px;
  flex-shrink: 0;
  background: rgba(255, 255, 255, 0.05);
  border-radius: 12px;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.metaphor-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.library-metaphor p {
  font-size: 0.9rem;
  color: #aaa;
  line-height: 1.5;
}

/* ========================================
   ERA INFO
   ======================================== */
.era-info {
  max-width: var(--content-max-width);
  margin: 0 auto;
  width: 100%;
}

.era-years {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #888;
  background: rgba(255, 255, 255, 0.1);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  margin-bottom: 0.5rem;
}

.era-info h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  margin-bottom: 1rem;
  color: #fff;
}

.era-description {
  font-size: 1.1rem;
  color: #bbb;
  max-width: 600px;
  margin-bottom: 1.5rem;
}

.physical-detail {
  background: rgba(255, 255, 255, 0.05);
  border-left: 3px solid rgba(255, 255, 255, 0.2);
  padding: 1rem 1.5rem;
  border-radius: 0 8px 8px 0;
  max-width: 600px;
}

.physical-detail h3 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #888;
  margin-bottom: 0.5rem;
}

.physical-detail p {
  font-size: 0.95rem;
  color: #999;
}

/* ========================================
   FOOTER
   ======================================== */
.footer {
  background: #0a0a0f;
  padding: 4rem 2rem;
  text-align: center;
  color: #666;
}

.footer p {
  margin-bottom: 0.5rem;
}

.footer .author-bio {
  font-size: 1rem;
  color: #888;
  margin-bottom: 1rem;
}

.footer .author-bio a {
  color: #4ecdc4;
  text-decoration: none;
  font-weight: 500;
}

.footer .author-bio a:hover {
  text-decoration: underline;
}

.footer .credits {
  font-size: 0.85rem;
  color: #444;
}

/* ========================================
   RESPONSIVE DESIGN
   ======================================== */
@media (max-width: 768px) {
  .strata-content {
    flex-direction: column;
  }

  .library-metaphor {
    width: 100%;
    flex-direction: row;
    gap: 1rem;
    text-align: left;
  }

  .metaphor-icon {
    font-size: 2rem;
    margin-bottom: 0;
  }

  .visualization-container {
    min-height: 300px;
  }
}

@media (max-width: 480px) {
  .strata {
    padding: 3rem 1rem;
  }

  .era-info h2 {
    font-size: 1.5rem;
  }
}

/* ========================================
   ANIMATION STATES
   ======================================== */
.strata.is-active .visualization-container {
  border-color: rgba(255, 255, 255, 0.25);
}

.strata.is-active .era-info h2 {
  animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
/* ========================================
   PROGRESS INDICATOR
   ======================================== */
.progress-nav {
  position: fixed;
  right: 20px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 100;
  display: flex;
  flex-direction: column;
  align-items: center;  /* Changed from flex-end */
  gap: 16px;
}

.progress-track {
  position: absolute;
  right: 50%;
  transform: translateX(50%);
  top: 10px;
  bottom: 10px;
  width: 2px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 1px;
}

.progress-dot {
  position: relative;
  display: block;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.3s ease;
}

.progress-dot .dot {
  display: block;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  border: 2px solid rgba(255, 255, 255, 0.3);
  transition: all 0.3s ease;
  position: relative;
  z-index: 1;
}

.progress-dot .label {
  position: absolute;
  right: 24px;
  top: 50%;
  transform: translateY(-50%) translateX(5px);
  font-size: 11px;
  color: rgba(255, 255, 255, 0.4);
  font-family: var(--font-mono);
  opacity: 0;
  transition: all 0.3s ease;
  white-space: nowrap;
  pointer-events: none;
}

.progress-dot:hover .label {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
}

.progress-dot:hover .dot {
  background: rgba(255, 255, 255, 0.4);
  border-color: rgba(255, 255, 255, 0.6);
  transform: scale(1.2);
}

/* Active state - set by scrollama */
.progress-dot.is-active .dot {
  background: #4ecdc4;
  border-color: #4ecdc4;
  box-shadow: 0 0 10px rgba(78, 205, 196, 0.5);
}

.progress-dot.is-active .label {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
  color: #4ecdc4;
}

/* Era-specific active colors */
.progress-dot[data-era="punch"].is-active .dot {
  background: var(--punch-secondary);
  border-color: var(--punch-secondary);
  box-shadow: 0 0 10px rgba(210, 105, 30, 0.5);
}

.progress-dot[data-era="tape"].is-active .dot {
  background: var(--tape-secondary);
  border-color: var(--tape-secondary);
  box-shadow: 0 0 10px rgba(112, 128, 144, 0.5);
}

.progress-dot[data-era="hdd"].is-active .dot {
  background: var(--hdd-secondary);
  border-color: var(--hdd-secondary);
  box-shadow: 0 0 10px rgba(74, 74, 106, 0.5);
}

.progress-dot[data-era="ssd"].is-active .dot {
  background: #4ecdc4;
  border-color: #4ecdc4;
  box-shadow: 0 0 10px rgba(78, 205, 196, 0.5);
}

.progress-dot[data-era="cloud"].is-active .dot {
  background: var(--cloud-secondary);
  border-color: var(--cloud-secondary);
  box-shadow: 0 0 10px rgba(184, 212, 227, 0.5);
}

/* Hide on mobile */
@media (max-width: 768px) {
  .progress-nav {
    display: none;
  }
}