/* ==========================================================================
   GPT-5.6 Sol - Premium Ethereal Glass Design System
   Site: gptsols.com | Target Keyword: GPT 5.6 Sol (gptsol)
   ========================================================================== */

/* Import Google Fonts - Outfit for Headers, Plus Jakarta Sans for Body, Geist Mono for Tech specs */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&family=Plus+Jakarta+Sans:wght@300;400;500;600;700&family=Geist+Mono:wght@300;400;500;600&display=swap');

/* --- Core Tokens & Root --- */
:root {
  --font-header: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: 'Geist Mono', monospace;

  /* Colors: OLED Dark + Solar Amber/Gold (representing "Sol") */
  --bg-oled: #030303;
  --bg-card-outer: rgba(255, 255, 255, 0.02);
  --bg-card-inner: rgba(10, 10, 10, 0.6);
  
  --color-sol-amber: #ff9130;
  --color-sol-gold: #ffc048;
  --color-sol-glow: rgba(255, 145, 48, 0.15);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --border-hairline: rgba(255, 255, 255, 0.07);
  --border-highlight: rgba(255, 255, 255, 0.15);
  
  --transition-bezier: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
}

/* --- Base Styles --- */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  background-color: var(--bg-oled);
  color: var(--text-primary);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  overflow-x: hidden;
  position: relative;
  min-height: 100dvh;
}

/* --- Noise Overlay for Cinematic Texture --- */
body::after {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  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");
  opacity: 0.015;
  pointer-events: none;
  z-index: 9999;
}

/* --- Glowing Solar Orbs (Sol Radial Gradients) --- */
.solar-orbs {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(140px);
  opacity: 0.45;
}

.orb-primary {
  top: -10%;
  right: 15%;
  width: 550px;
  height: 550px;
  background: radial-gradient(circle, var(--color-sol-amber) 0%, rgba(255, 107, 0, 0.4) 50%, transparent 100%);
}

.orb-secondary {
  top: 25%;
  left: -10%;
  width: 450px;
  height: 450px;
  background: radial-gradient(circle, rgba(147, 51, 234, 0.3) 0%, rgba(79, 70, 229, 0.2) 60%, transparent 100%);
}

.orb-tertiary {
  bottom: 10%;
  right: -5%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(255, 145, 48, 0.25) 0%, rgba(219, 39, 119, 0.1) 60%, transparent 100%);
}

/* --- Layout System --- */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 10;
}

section {
  padding: 120px 0;
  position: relative;
}

@media (max-width: 768px) {
  section {
    padding: 80px 0;
  }
}

/* --- Typography --- */
h1, h2, h3, h4 {
  font-family: var(--font-header);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.05;
  color: var(--text-primary);
}

p {
  font-family: var(--font-body);
  font-size: 1.05rem;
  line-height: 1.6;
  color: var(--text-secondary);
}

.text-gradient {
  background: linear-gradient(135deg, #ffffff 30%, var(--color-sol-gold) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.mono-tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--color-sol-amber);
  display: inline-block;
  margin-bottom: 16px;
}

/* --- Navigation --- */
.nav-wrapper {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  padding: 24px 0;
  transition: transform 0.4s var(--transition-bezier), background-color 0.3s;
}

.nav-scrolled {
  background-color: rgba(5, 5, 5, 0.7);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-hairline);
  padding: 16px 0;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.logo {
  font-family: var(--font-header);
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  text-decoration: none;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo span {
  color: var(--color-sol-amber);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  color: var(--text-secondary);
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--text-primary);
}

/* Interactive Hamburger */
.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  z-index: 1001;
  padding: 8px;
}

.hamburger-line {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  margin: 5px 0;
  transition: transform 0.3s var(--transition-spring), opacity 0.3s;
}

/* Active Menu Overlay */
.mobile-menu {
  position: fixed;
  inset: 0;
  background-color: rgba(3, 3, 3, 0.95);
  backdrop-filter: blur(24px);
  z-index: 999;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.4s var(--transition-bezier), visibility 0.4s;
}

.mobile-menu.active {
  opacity: 1;
  visibility: visible;
}

.mobile-links {
  list-style: none;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.mobile-links a {
  font-family: var(--font-header);
  font-size: 2.2rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text-secondary);
  transition: color 0.3s, transform 0.3s;
  display: block;
  transform: translateY(20px);
  opacity: 0;
}

.mobile-menu.active .mobile-links a {
  transform: translateY(0);
  opacity: 1;
  transition: transform 0.5s var(--transition-bezier), opacity 0.5s;
}

.mobile-menu.active .mobile-links li:nth-child(1) a { transition-delay: 0.1s; }
.mobile-menu.active .mobile-links li:nth-child(2) a { transition-delay: 0.15s; }
.mobile-menu.active .mobile-links li:nth-child(3) a { transition-delay: 0.2s; }
.mobile-menu.active .mobile-links li:nth-child(4) a { transition-delay: 0.25s; }
.mobile-menu.active .mobile-links li:nth-child(5) a { transition-delay: 0.3s; }

/* Hamburger Morph into X */
.hamburger.active .hamburger-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger.active .hamburger-line:nth-child(2) {
  opacity: 0;
}

.hamburger.active .hamburger-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: block; }
}

/* --- Hero Section --- */
.hero {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  padding-top: 140px;
  position: relative;
  z-index: 10;
}

.hero-content {
  max-width: 800px;
  text-align: center;
  margin: 0 auto;
}

.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.8rem);
  margin-bottom: 24px;
  line-height: 1.0;
}

.hero-desc {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  max-width: 650px;
  margin: 0 auto 40px auto;
  color: var(--text-secondary);
}

.hero-ctas {
  display: flex;
  gap: 16px;
  justify-content: center;
  align-items: center;
}

@media (max-width: 480px) {
  .hero-ctas {
    flex-direction: column;
    width: 100%;
  }
}

/* --- Double-Bezel Nested Card Architecture --- */
.card-outer {
  background-color: var(--bg-card-outer);
  border: 1px solid var(--border-hairline);
  padding: 8px;
  border-radius: 2rem;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: transform 0.5s var(--transition-bezier), border-color 0.5s;
}

.card-inner {
  background-color: var(--bg-card-inner);
  border: 1px solid rgba(255, 255, 255, 0.05);
  border-radius: calc(2rem - 8px);
  padding: 32px;
  height: 100%;
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.05);
  transition: background-color 0.5s;
}

.card-outer:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 145, 48, 0.3);
}

.card-outer:hover .card-inner {
  background-color: rgba(20, 20, 20, 0.7);
}

/* --- Grid Systems (Bento style) --- */
.grid-bento {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: 24px;
}

.bento-8 { grid-column: span 8; }
.bento-4 { grid-column: span 4; }
.bento-6 { grid-column: span 6; }
.bento-12 { grid-column: span 12; }

@media (max-width: 1024px) {
  .bento-8, .bento-4, .bento-6 {
    grid-column: span 12;
  }
}

/* --- Featured Grid Archetype --- */
.features-grid {
  margin-top: 64px;
}

.feature-icon-wrapper {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background-color: rgba(255, 145, 48, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  border: 1px solid rgba(255, 145, 48, 0.2);
}

.feature-icon-wrapper svg {
  width: 24px;
  height: 24px;
  stroke: var(--color-sol-amber);
}

.card-title {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.card-desc {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

/* --- Button Engine --- */
.btn {
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 9999px;
  padding: 12px 28px;
  display: inline-flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  transition: transform 0.2s var(--transition-spring), opacity 0.3s;
  outline: none;
}

.btn-primary {
  background-color: var(--text-primary);
  color: var(--bg-oled);
  border: 1px solid transparent;
}

/* Button-in-Button Arrow */
.btn-arrow-wrapper {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background-color: rgba(3, 3, 3, 0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.4s var(--transition-bezier), background-color 0.3s;
}

.btn-arrow-wrapper svg {
  width: 14px;
  height: 14px;
  stroke: var(--bg-oled);
  stroke-width: 2;
  transition: stroke 0.3s;
}

/* Dark mode version arrow styles */
.btn-primary:hover .btn-arrow-wrapper {
  transform: translateX(3px) rotate(45deg);
  background-color: var(--color-sol-amber);
}

.btn-primary:hover .btn-arrow-wrapper svg {
  stroke: var(--text-primary);
}

.btn-secondary {
  background-color: rgba(255, 255, 255, 0.03);
  color: var(--text-primary);
  border: 1px solid var(--border-hairline);
  backdrop-filter: blur(8px);
}

.btn-secondary:hover {
  background-color: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.2);
}

.btn-secondary .btn-arrow-wrapper {
  background-color: rgba(255, 255, 255, 0.05);
}

.btn-secondary .btn-arrow-wrapper svg {
  stroke: var(--text-primary);
}

.btn-secondary:hover .btn-arrow-wrapper {
  transform: translateX(3px) rotate(45deg);
  background-color: var(--color-sol-amber);
}

.btn:active {
  transform: scale(0.97);
}

@media (max-width: 480px) {
  .btn {
    width: 100%;
    justify-content: center;
  }
}

/* --- Compare Section (Model Tiers Matrix) --- */
.compare-container {
  margin-top: 48px;
  overflow-x: auto;
  border: 1px solid var(--border-hairline);
  border-radius: 1.5rem;
  background-color: rgba(255, 255, 255, 0.01);
  backdrop-filter: blur(12px);
}

table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  min-width: 600px;
}

th, td {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-hairline);
  font-size: 0.95rem;
}

th {
  font-family: var(--font-header);
  font-weight: 600;
  color: var(--text-primary);
  background-color: rgba(255, 255, 255, 0.02);
}

td {
  color: var(--text-secondary);
}

tr:last-child td {
  border-bottom: none;
}

.tier-badge {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.badge-sol {
  background-color: rgba(255, 145, 48, 0.1);
  color: var(--color-sol-amber);
  border: 1px solid rgba(255, 145, 48, 0.2);
}

.badge-terra {
  background-color: rgba(56, 189, 248, 0.1);
  color: #38bdf8;
  border: 1px solid rgba(56, 189, 248, 0.2);
}

.badge-luna {
  background-color: rgba(168, 85, 247, 0.1);
  color: #a855f7;
  border: 1px solid rgba(168, 85, 247, 0.2);
}

/* --- FAQ Accordion --- */
.faq-list {
  max-width: 800px;
  margin: 48px auto 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border-hairline);
  padding: 24px 0;
}

.faq-trigger {
  width: 100%;
  background: none;
  border: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  text-align: left;
  cursor: pointer;
  color: var(--text-primary);
  font-family: var(--font-header);
  font-size: 1.2rem;
  font-weight: 600;
  gap: 16px;
}

.faq-icon {
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.4s var(--transition-bezier);
}

.faq-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--text-secondary);
}

.faq-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s var(--transition-bezier);
}

.faq-content p {
  padding-top: 16px;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-item.active .faq-icon svg {
  stroke: var(--color-sol-amber);
}

/* --- Footer --- */
footer {
  border-top: 1px solid var(--border-hairline);
  padding: 64px 0;
  background-color: rgba(3, 3, 3, 0.9);
  text-align: center;
  position: relative;
  z-index: 10;
}

.footer-logo {
  font-family: var(--font-header);
  font-size: 1.6rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--text-primary);
  margin-bottom: 16px;
  display: inline-block;
  text-decoration: none;
}

.footer-logo span {
  color: var(--color-sol-amber);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 24px;
  list-style: none;
}

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9rem;
  transition: color 0.3s;
}

.footer-links a:hover {
  color: var(--text-primary);
}

.footer-copyright {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* --- Animation Utilities (Scroll Reveal) --- */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  filter: blur(4px);
  transition: opacity 0.8s var(--transition-bezier), transform 0.8s var(--transition-bezier), filter 0.8s var(--transition-bezier);
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
  filter: blur(0);
}

.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }

/* Accessibility: Respect Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-delay: 0s !important;
    animation-duration: 0s !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0s !important;
    scroll-behavior: auto !important;
  }
  .reveal {
    opacity: 1 !important;
    transform: none !important;
    filter: none !important;
  }
  .card-outer:hover {
    transform: none !important;
  }
}

/* --- Pure CSS Fade In on Load (For Subpages/Article Hub) --- */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(24px);
    filter: blur(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
    filter: blur(0);
  }
}

.fade-in-load {
  animation: fadeIn 0.8s var(--transition-bezier) forwards;
}