/*
 * Om Saravana Bhava — Premium Phase 4 (2026)
 * Scope: murugan-timeline.html, sloka-library.html, platform-hub.html, discovery.html
 * CSS-only interaction layer. No existing JavaScript ownership is changed.
 */

.phase4-page {
  --p4-gold: var(--gold, #d9a52c);
  --p4-gold-2: #ffe2a0;
  --p4-saffron: #e8750a;
  --p4-ruby: #8f2436;
  --p4-peacock: #176b82;
  --p4-ink: #17131d;
  --p4-panel: rgba(255,255,255,.94);
  --p4-line: rgba(151,91,28,.18);
  --p4-shadow: 0 24px 70px rgba(45,24,10,.13);
  --p4-shadow-soft: 0 12px 36px rgba(45,24,10,.09);
  --p4-radius: 24px;
  background:
    radial-gradient(circle at 8% 0%, rgba(232,117,10,.11), transparent 30rem),
    radial-gradient(circle at 95% 10%, rgba(23,107,130,.10), transparent 34rem),
    var(--bg, #fff7ec);
  min-height: 100vh;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

.phase4-page .wrap {
  width: min(1180px, calc(100% - 32px));
}

.phase4-page .top {
  letter-spacing: .035em;
}

.phase4-page .nav {
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 1px 0 rgba(151,91,28,.12);
}

.phase4-page .nav a[aria-current="page"] {
  color: var(--p4-gold);
  background: rgba(217,165,44,.11);
  border-radius: 999px;
}

.phase4-page a,
.phase4-page button,
.phase4-page input,
.phase4-page select {
  transition:
    transform .22s ease,
    box-shadow .22s ease,
    border-color .22s ease,
    background-color .22s ease,
    color .22s ease;
}

.phase4-page a:focus-visible,
.phase4-page button:focus-visible,
.phase4-page input:focus-visible,
.phase4-page select:focus-visible {
  outline: 3px solid var(--p4-gold);
  outline-offset: 3px;
}

.phase4-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  margin-block: 1rem 2rem;
  padding: clamp(2rem, 5vw, 4.5rem);
  border: 1px solid rgba(217,165,44,.26);
  border-radius: clamp(24px, 4vw, 40px);
  background:
    linear-gradient(125deg, rgba(255,255,255,.97), rgba(255,248,232,.91)),
    radial-gradient(circle at 90% 20%, rgba(217,165,44,.22), transparent 24rem);
  box-shadow: var(--p4-shadow);
}

.phase4-hero::before,
.phase4-hero::after {
  content: "";
  position: absolute;
  z-index: -1;
  pointer-events: none;
  border-radius: 50%;
}

.phase4-hero::before {
  width: 26rem;
  height: 26rem;
  right: -11rem;
  top: -13rem;
  background: radial-gradient(circle, rgba(232,117,10,.20), transparent 68%);
}

.phase4-hero::after {
  width: 18rem;
  height: 18rem;
  left: -10rem;
  bottom: -11rem;
  background: radial-gradient(circle, rgba(23,107,130,.16), transparent 70%);
}

.phase4-eyebrow {
  margin: 0 0 .7rem;
  color: #8a5d12;
  font-size: .76rem;
  font-weight: 800;
  letter-spacing: .18em;
  text-transform: uppercase;
}

.phase4-lead {
  max-width: 72ch;
  font-size: clamp(1.05rem, 1.8vw, 1.28rem);
  line-height: 1.75;
  color: var(--muted, #685a52);
}

.phase4-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .8rem;
  margin-top: 1.5rem;
}

.phase4-actions .btn,
.phase4-page .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.phase4-page .btn:hover,
.phase4-page .premium-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px rgba(124,75,14,.18);
}

.phase4-section-heading {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(240px, .8fr);
  gap: 2rem;
  align-items: end;
  margin: 3rem 0 1.25rem;
}

.phase4-section-heading h2,
.phase4-page section > h2 {
  text-wrap: balance;
}

.phase4-page .card {
  border: 1px solid var(--p4-line);
  box-shadow: var(--p4-shadow-soft);
}

.phase4-page .card:hover {
  border-color: rgba(217,165,44,.42);
  box-shadow: 0 20px 46px rgba(45,24,10,.14);
}

.phase4-featured {
  position: relative;
  overflow: hidden;
  margin-bottom: 2rem;
}

.phase4-featured::after {
  content: "வேல்";
  position: absolute;
  right: 1rem;
  bottom: -.35rem;
  color: rgba(217,165,44,.10);
  font: 800 clamp(4rem, 12vw, 8rem)/1 Georgia, serif;
  pointer-events: none;
}

.phase4-content-grid > .card,
.phase4-route-results > .card,
.phase4-support-grid > .card,
.phase4-pathway-grid > .premium-card,
.phase4-quality-grid > .premium-card,
.phase4-route-grid > .premium-card {
  content-visibility: auto;
  contain-intrinsic-size: 320px;
}

/* Timeline */
.phase4-timeline {
  position: relative;
  display: grid;
  gap: 1.1rem;
  margin: 1.5rem 0 3rem;
  padding-left: 3.25rem;
}

.phase4-timeline::before {
  content: "";
  position: absolute;
  left: 1.15rem;
  top: 1rem;
  bottom: 1rem;
  width: 2px;
  background: linear-gradient(var(--p4-gold), rgba(217,165,44,.12));
}

.phase4-timeline .card {
  position: relative;
  margin: 0;
  padding: clamp(1.25rem, 3vw, 2rem);
  border-radius: var(--p4-radius);
  background:
    linear-gradient(135deg, rgba(255,255,255,.98), rgba(255,249,237,.94));
}

.phase4-timeline .card::before {
  content: counter(p4timeline);
  counter-increment: p4timeline;
  position: absolute;
  left: -3.25rem;
  top: 1.35rem;
  width: 2.25rem;
  height: 2.25rem;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #26180b;
  background: linear-gradient(135deg, var(--p4-gold-2), var(--p4-gold));
  box-shadow: 0 0 0 6px var(--bg, #fff7ec), 0 8px 20px rgba(124,75,14,.18);
  font-weight: 900;
}

.phase4-timeline {
  counter-reset: p4timeline;
}

.phase4-timeline .card:hover {
  transform: translateX(5px);
}

.phase4-timeline h2 {
  margin-bottom: .15rem;
  font-family: Georgia, "Noto Serif Tamil", serif;
  font-size: clamp(1.55rem, 3vw, 2.25rem);
}

.phase4-timeline h3 {
  margin-top: 0;
  color: #6e4915;
}

.phase4-boundary {
  border-left: 5px solid var(--p4-gold) !important;
  background:
    linear-gradient(120deg, rgba(255,255,255,.98), rgba(255,244,219,.88)) !important;
}

/* Sloka library */
.sloka-page .phase4-content-grid {
  gap: 1.15rem;
}

.sloka-page .phase4-content-grid .card {
  position: relative;
  overflow: hidden;
  border-radius: var(--p4-radius);
  background:
    linear-gradient(145deg, rgba(255,255,255,.98), rgba(255,247,232,.94));
}

.sloka-page .phase4-content-grid .card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 3px;
  background: linear-gradient(90deg, var(--p4-ruby), var(--p4-gold), var(--p4-peacock));
}

.sloka-page .phase4-content-grid .card:hover {
  transform: translateY(-4px);
}

.sloka-page .tools {
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 16px 44px rgba(45,24,10,.20);
}

.sloka-page .tool {
  min-height: 44px;
}

/* Platform hub */
.hub-page {
  --p4-panel: rgba(18,12,24,.82);
}

.hub-page .phase4-hub-hero {
  min-height: min(720px, 80vh);
}

.hub-page .phase4-metrics {
  transform: translateY(-1.25rem);
}

.hub-page .phase4-pathway-grid .premium-card,
.hub-page .phase4-quality-grid .premium-card,
.hub-page .phase4-route-grid .premium-card {
  position: relative;
  overflow: hidden;
}

.hub-page .phase4-pathway-grid .premium-card::after,
.hub-page .phase4-quality-grid .premium-card::after {
  content: "";
  position: absolute;
  inset: auto -20% -55% 35%;
  height: 11rem;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(242,189,84,.12), transparent 68%);
  pointer-events: none;
}

.hub-page .phase4-pathway-grid .premium-card:hover,
.hub-page .phase4-route-grid .premium-card:hover,
.hub-page .phase4-quality-grid .premium-card:hover {
  transform: translateY(-5px);
  border-color: rgba(242,189,84,.42);
}

.hub-page .phase4-toolbar {
  position: sticky;
  top: 86px;
  z-index: 15;
  padding: 1rem;
  border: 1px solid rgba(242,189,84,.18);
  background: rgba(14,12,20,.92);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 16px 50px rgba(0,0,0,.30);
}

/* Discovery */
.discovery-page .discovery-hero {
  align-items: stretch;
}

.discovery-page .discovery-metric {
  min-height: 126px;
  display: grid;
  align-content: center;
  border: 1px solid rgba(217,165,44,.20);
  border-radius: 20px;
  background: rgba(255,255,255,.72);
  box-shadow: var(--p4-shadow-soft);
}

.phase4-discovery-workspace {
  align-items: start;
}

.phase4-controls {
  position: sticky;
  top: 92px;
  border-radius: var(--p4-radius);
}

.phase4-controls input,
.phase4-controls select,
.hub-page .phase4-toolbar input,
.hub-page .phase4-toolbar select {
  min-height: 46px;
  border-radius: 12px;
}

.phase4-results-panel {
  min-width: 0;
}

.phase4-route-results .card {
  border-radius: 20px;
}

.phase4-route-results .card:hover {
  transform: translateY(-3px);
}

.phase4-support-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  margin-block: 2rem;
}

.phase4-support-grid .card {
  margin: 0;
  display: flex;
  flex-direction: column;
}

.phase4-support-grid .btn {
  margin-top: auto;
  align-self: flex-start;
}

/* Responsive */
@media (max-width: 900px) {
  .phase4-section-heading,
  .phase4-support-grid {
    grid-template-columns: 1fr 1fr;
  }

  .hub-page .phase4-toolbar,
  .phase4-controls {
    position: static;
  }
}

@media (max-width: 680px) {
  .phase4-page .wrap {
    width: min(100% - 20px, 1180px);
  }

  .phase4-hero {
    padding: 1.4rem;
    border-radius: 24px;
  }

  .phase4-section-heading,
  .phase4-support-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .phase4-actions {
    display: grid;
  }

  .phase4-actions .btn {
    width: 100%;
  }

  .phase4-timeline {
    padding-left: 2.75rem;
  }

  .phase4-timeline::before {
    left: .9rem;
  }

  .phase4-timeline .card::before {
    left: -2.8rem;
    width: 2rem;
    height: 2rem;
  }

  .hub-page .phase4-hub-hero {
    min-height: auto;
  }
}

/* Accessibility and user preferences */
@media (prefers-reduced-motion: reduce) {
  .phase4-page *,
  .phase4-page *::before,
  .phase4-page *::after {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (forced-colors: active) {
  .phase4-page .card,
  .phase4-hero,
  .phase4-page .premium-card {
    border: 1px solid CanvasText;
  }
}

@media print {
  .phase4-page .nav,
  .phase4-page .top,
  .phase4-page .tools,
  .phase4-actions {
    display: none !important;
  }

  .phase4-page,
  .phase4-hero,
  .phase4-page .card {
    color: #000 !important;
    background: #fff !important;
    box-shadow: none !important;
  }
}