/* -------------------------------------------------------------
 * KRIYA QUEST DESIGN SYSTEM & STYLE SHEET
 * Dual Theme (Light & Dark) with Floating Science Graphics
 * Optimized for Mobile-First Touch Interactions
 * ------------------------------------------------------------- */

/* Theme Variables */
:root {
  /* Common Accent Colors (Vibrant STEM Palette) */
  --accent-orange: #ff6900;       /* STEM Orange */
  --accent-orange-hsl: 25, 100%, 50%;
  --accent-cyan: #0693e3;         /* STEM Cyan/Blue */
  --accent-cyan-hsl: 202, 95%, 46%;

  /* --- LIGHT THEME (Default) --- */
  --primary-color: #091e3a;        /* Deep Navy */
  --bg-light: #f6f8fb;            /* Soft slate white */
  --white: #ffffff;
  --text-dark: #1e293b;           /* Charcoal */
  --text-muted: #64748b;          /* Muted slate */
  --border-color: #e2e8f0;        /* Light grey border */
  --accordion-bg: #fafbfc;
  --header-bg: rgba(255, 255, 255, 0.85);
  
  --shadow-premium: 0 20px 40px -15px rgba(9, 30, 58, 0.06), 0 0 0 1px rgba(9, 30, 58, 0.02);
  --shadow-glow-build: 0 10px 20px -5px rgba(9, 30, 58, 0.25);
  --shadow-glow-understand: 0 10px 20px -5px rgba(255, 105, 0, 0.25);
  --shadow-glow-explore: 0 10px 20px -5px rgba(6, 147, 227, 0.25);
  
  --floating-icon-opacity: 0.08;
  --grid-line-color: rgba(9, 30, 58, 0.03);
  
  /* Styling Tokens */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-serif: 'Roboto Slab', Georgia, serif;
  --border-radius-lg: 24px;
  --border-radius-md: 16px;
  --border-radius-sm: 8px;
  --transition-smooth: all 0.4s cubic-bezier(0.25, 1, 0.5, 1);
}

/* --- DARK THEME --- */
body.dark {
  --primary-color: #f8fafc;        /* Off-white */
  --bg-light: #050b14;             /* Space Dark */
  --white: #0a1224;               /* Cyber Dark Card */
  --text-dark: #f8fafc;           /* Light grey text */
  --text-muted: #94a3b8;          /* Slate */
  --border-color: rgba(255, 255, 255, 0.08);
  --accordion-bg: #0d172e;
  --header-bg: rgba(10, 18, 36, 0.85);
  
  --shadow-premium: 0 25px 50px -12px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.05);
  --shadow-glow-build: 0 10px 25px -5px rgba(255, 255, 255, 0.15);
  --shadow-glow-understand: 0 10px 25px -5px rgba(255, 105, 0, 0.4);
  --shadow-glow-explore: 0 10px 25px -5px rgba(6, 147, 227, 0.4);
  
  --floating-icon-opacity: 0.22;
  --grid-line-color: rgba(255, 255, 255, 0.02);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-light);
  color: var(--text-dark);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow-x: hidden;
  transition: background-color 0.5s ease, color 0.5s ease;
  
  /* Science Blueprint Grid Pattern */
  background-image: 
    linear-gradient(var(--grid-line-color) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line-color) 1px, transparent 1px);
  background-size: 32px 32px;
}

/* Soft glowing mesh gradient bubbles in background */
body::before {
  content: "";
  position: absolute;
  top: -10%;
  right: -10%;
  width: 60vw;
  height: 60vw;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(6, 147, 227, 0.08) 0%, rgba(255, 255, 255, 0) 70%);
  z-index: -1;
  pointer-events: none;
  transition: background 0.5s ease;
}

body::after {
  content: "";
  position: absolute;
  bottom: -10%;
  left: -10%;
  width: 50vw;
  height: 50vw;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 105, 0, 0.05) 0%, rgba(255, 255, 255, 0) 70%);
  z-index: -1;
  pointer-events: none;
  transition: background 0.5s ease;
}

/* Dark mode glowing mesh gradient bubbles */
body.dark::before {
  background: radial-gradient(circle at 80% 10%, rgba(6, 147, 227, 0.16) 0%, rgba(5, 11, 20, 0) 60%);
}
body.dark::after {
  background: radial-gradient(circle at 20% 90%, rgba(255, 105, 0, 0.12) 0%, rgba(5, 11, 20, 0) 60%);
}

/* -------------------------------------------------------------
 * FLOATING SCIENCE GRAPHICS BACKGROUND
 * ------------------------------------------------------------- */
.floating-background {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.float-icon {
  position: absolute;
  width: 65px;
  height: 65px;
  opacity: var(--floating-icon-opacity);
  transition: opacity 0.5s ease, color 0.5s ease;
  animation: floatAnimation 25s infinite linear;
}

/* Unique Floating Animations for different icons to look organic */
.icon-atom { animation-duration: 22s; color: var(--text-muted); }
.icon-flask { animation-duration: 28s; animation-delay: -5s; color: var(--text-muted); }
.icon-microscope { animation-duration: 32s; animation-delay: -10s; color: var(--text-muted); }
.icon-dna { animation-duration: 26s; animation-delay: -15s; color: var(--text-muted); }
.icon-gear { animation-duration: 24s; animation-delay: -3s; color: var(--text-muted); }
.icon-spark { animation-duration: 18s; animation-delay: -8s; color: var(--text-muted); }

/* Dark mode neon coloring & glowing shadows */
body.dark .icon-atom { color: var(--accent-orange); filter: drop-shadow(0 0 10px rgba(255, 105, 0, 0.5)); }
body.dark .icon-flask { color: var(--accent-cyan); filter: drop-shadow(0 0 10px rgba(6, 147, 227, 0.5)); }
body.dark .icon-microscope { color: var(--accent-orange); filter: drop-shadow(0 0 10px rgba(255, 105, 0, 0.4)); }
body.dark .icon-dna { color: var(--accent-cyan); filter: drop-shadow(0 0 10px rgba(6, 147, 227, 0.5)); }
body.dark .icon-gear { color: var(--accent-orange); filter: drop-shadow(0 0 10px rgba(255, 105, 0, 0.4)); }
body.dark .icon-spark { color: var(--accent-cyan); filter: drop-shadow(0 0 10px rgba(6, 147, 227, 0.5)); }

@keyframes floatAnimation {
  0% {
    transform: translateY(0) rotate(0deg) scale(1);
  }
  50% {
    transform: translateY(-30px) rotate(180deg) scale(1.08);
  }
  100% {
    transform: translateY(0) rotate(360deg) scale(1);
  }
}

/* -------------------------------------------------------------
 * HEADER
 * ------------------------------------------------------------- */
.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: var(--header-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
  transition: background-color 0.5s ease, border-color 0.5s ease;
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 14px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo-link {
  display: flex;
  align-items: center;
}

.logo-img {
  height: 48px;
  width: auto;
  transition: var(--transition-smooth);
}

body.dark .logo-img {
  filter: brightness(1.15) contrast(1.05); /* Enhance logo readability in dark mode */
}

.logo-img:hover {
  transform: scale(1.03);
}

/* Theme Toggle Button */
.theme-toggle-btn {
  background: transparent;
  border: 2px solid var(--border-color);
  color: var(--primary-color);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.theme-toggle-btn:hover {
  background-color: rgba(9, 30, 58, 0.05);
  transform: rotate(15deg) scale(1.05);
}

body.dark .theme-toggle-btn {
  color: var(--accent-orange);
  border-color: rgba(255, 255, 255, 0.15);
}

body.dark .theme-toggle-btn:hover {
  background-color: rgba(255, 255, 255, 0.08);
}

.theme-icon {
  width: 20px;
  height: 20px;
  stroke: currentColor;
}

/* Manage Sun/Moon icons pure CSS */
body:not(.dark) #sunIcon { display: none !important; }
body.dark #moonIcon { display: none !important; }

/* -------------------------------------------------------------
 * MAIN LAYOUT & CARDS
 * ------------------------------------------------------------- */
.main-content {
  flex-grow: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 24px;
  z-index: 2;
  position: relative;
}

.card-container {
  background-color: var(--white);
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-premium);
  width: 100%;
  max-width: 800px;
  padding: 40px;
  position: relative;
  transition: background-color 0.5s ease, border-color 0.5s ease, box-shadow 0.5s ease;
}

body.dark .card-container {
  background: linear-gradient(145deg, #0a1224, #060b18);
}

/* Loading & Error States */
.loading-state, .error-state {
  text-align: center;
  padding: 40px 0;
}

.spinner {
  width: 48px;
  height: 48px;
  border: 4px solid rgba(6, 147, 227, 0.1);
  border-top: 4px solid var(--accent-cyan);
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin: 0 auto 20px;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.loading-state p {
  color: var(--text-muted);
  font-weight: 500;
  font-size: 15px;
}

.error-state .error-icon {
  color: #ef4444;
  margin-bottom: 20px;
}

.error-state .error-icon svg {
  width: 64px;
  height: 64px;
}

.error-state h2 {
  font-family: var(--font-serif);
  color: var(--text-dark);
  margin-bottom: 12px;
}

.error-state p {
  color: var(--text-muted);
  margin-bottom: 24px;
}

.hidden {
  display: none !important;
}

/* -------------------------------------------------------------
 * EXPERIMENT CONTENT
 * ------------------------------------------------------------- */
.experiment-header {
  text-align: center;
  margin-bottom: 32px;
}

.badge {
  display: inline-block;
  background-color: rgba(255, 105, 0, 0.1);
  color: var(--accent-orange);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 1.5px;
  padding: 6px 16px;
  border-radius: 50px;
  margin-bottom: 12px;
  text-transform: uppercase;
}

body.dark .badge {
  background-color: rgba(255, 105, 0, 0.18);
  box-shadow: 0 0 10px rgba(255, 105, 0, 0.1);
}

.experiment-title {
  font-family: var(--font-serif);
  font-size: 36px;
  font-weight: 700;
  color: var(--text-dark);
  margin-bottom: 16px;
}

.accent-line {
  width: 64px;
  height: 4px;
  background: linear-gradient(90deg, var(--accent-orange) 0%, var(--accent-cyan) 100%);
  border-radius: 2px;
  margin: 0 auto;
}

/* Manual Link Container */
.manual-container {
  display: flex;
  justify-content: center;
  margin-bottom: 32px;
}

/* -------------------------------------------------------------
 * BUTTONS GRID (DYNAMIC LAYOUT SCALING)
 * ------------------------------------------------------------- */
.buttons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}

/* Button & Link base classes */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn-primary {
  background-color: var(--accent-orange);
  color: var(--white);
  border: none;
}

.btn-primary:hover {
  background-color: #e05c00;
  transform: translateY(-2px);
  box-shadow: 0 6px 16px rgba(255, 105, 0, 0.3);
}

.btn-outline {
  background-color: transparent;
  border: 2px solid var(--border-color);
  color: var(--text-dark);
}

.btn-outline:hover {
  border-color: var(--text-dark);
  background-color: rgba(9, 30, 58, 0.03);
}

body.dark .btn-outline:hover {
  background-color: rgba(255, 255, 255, 0.03);
  border-color: var(--white);
}

.btn-icon {
  width: 18px;
  height: 18px;
  margin-right: 8px;
}

/* Dynamic Tab Buttons */
.tab-button {
  background-color: var(--white);
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-md);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  cursor: pointer;
  text-align: left;
  transition: var(--transition-smooth);
  outline: none;
}

body.dark .tab-button {
  background-color: #0d162d;
}

.tab-button:hover {
  border-color: var(--text-muted);
  transform: translateY(-3px);
}

body.dark .tab-button:hover {
  border-color: rgba(255, 255, 255, 0.2);
}

.tab-button-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  transition: var(--transition-smooth);
}

.tab-button-icon svg {
  width: 22px;
  height: 22px;
}

/* Sub-titles and labels in buttons */
.tab-subtitle {
  display: block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.75px;
  text-transform: uppercase;
  color: var(--text-muted);
  transition: var(--transition-smooth);
}

.tab-title {
  display: block;
  font-size: 16px;
  font-weight: 700;
  color: var(--text-dark);
  transition: var(--transition-smooth);
}

/* --- Color Themed Unselected States --- */
#buttonBuild .tab-button-icon {
  background-color: rgba(9, 30, 58, 0.05);
  color: var(--primary-color);
}
#buttonUnderstand .tab-button-icon {
  background-color: rgba(255, 105, 0, 0.06);
  color: var(--accent-orange);
}
#buttonExplore .tab-button-icon {
  background-color: rgba(6, 147, 227, 0.06);
  color: var(--accent-cyan);
}

body.dark #buttonBuild .tab-button-icon {
  background-color: rgba(255, 255, 255, 0.06);
  color: #cbd5e1;
}

/* --- Active Tab Button States --- */
.tab-button.active {
  border-color: transparent !important;
}

.tab-button.active .tab-subtitle {
  color: rgba(255, 255, 255, 0.8) !important;
}

.tab-button.active .tab-title {
  color: var(--white) !important;
}

/* Build Button Active */
.tab-button.active#buttonBuild {
  background-color: var(--primary-color);
  box-shadow: var(--shadow-glow-build);
}
body.dark .tab-button.active#buttonBuild {
  background-color: #1e293b; /* Pure dark grey for build */
}
.tab-button.active#buttonBuild .tab-button-icon {
  background-color: rgba(255, 255, 255, 0.15);
  color: var(--white);
}

/* Understand Button Active */
.tab-button.active#buttonUnderstand {
  background-color: var(--accent-orange);
  box-shadow: var(--shadow-glow-understand);
}
.tab-button.active#buttonUnderstand .tab-button-icon {
  background-color: rgba(255, 255, 255, 0.2);
  color: var(--white);
}

/* Explore Button Active */
.tab-button.active#buttonExplore {
  background-color: var(--accent-cyan);
  box-shadow: var(--shadow-glow-explore);
}
.tab-button.active#buttonExplore .tab-button-icon {
  background-color: rgba(255, 255, 255, 0.2);
  color: var(--white);
}

/* -------------------------------------------------------------
 * ACCORDION CONTAINER & VIDEO PLAYER
 * ------------------------------------------------------------- */
.accordions-container {
  margin-top: 16px;
}

.accordion-box {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 0.4s cubic-bezier(0.25, 1, 0.5, 1);
  overflow: hidden;
  border-radius: var(--border-radius-md);
}

.accordion-box.expanded {
  grid-template-rows: 1fr;
  border: 1px solid var(--border-color);
  background-color: var(--accordion-bg);
  margin-bottom: 24px;
}

.accordion-inner {
  min-height: 0;
  visibility: hidden;
  opacity: 0;
  transition: opacity 0.3s ease, visibility 0.3s ease;
  padding: 0 24px 24px;
}

.accordion-box.expanded .accordion-inner {
  visibility: visible;
  opacity: 1;
  padding-top: 24px;
}

/* Video Player Frame Styling */
.video-container {
  position: relative;
  aspect-ratio: 16/9;
  width: 100%;
  border-radius: var(--border-radius-md);
  overflow: hidden;
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.3);
  background-color: #000;
  margin-bottom: 20px;
}

.video-iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.video-info h3 {
  font-family: var(--font-sans);
  color: var(--text-dark);
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.video-info p {
  color: var(--text-muted);
  font-size: 14.5px;
}

/* -------------------------------------------------------------
 * FOOTER
 * ------------------------------------------------------------- */
.footer {
  background-color: #091e3a; /* Footer stays deep navy for premium branding */
  color: var(--white);
  padding: 40px 24px;
  text-align: center;
  border-top: 4px solid var(--accent-orange);
  z-index: 2;
  position: relative;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
}

.footer .tagline {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 2.5px;
  text-transform: uppercase;
  color: var(--accent-cyan);
  margin-bottom: 20px;
}

.footer-links {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 16px;
  margin-bottom: 20px;
}

.footer-link {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  transition: var(--transition-smooth);
}

.footer-link:hover {
  color: var(--white);
  text-decoration: underline;
}

.footer-dot {
  color: rgba(255, 255, 255, 0.3);
  font-size: 10px;
}

.footer .copyright {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.4);
}

/* -------------------------------------------------------------
 * PHONE OPTIMIZATION & RESPONSIVENESS (MOBILE-FIRST)
 * ------------------------------------------------------------- */
@media (max-width: 768px) {
  /* Blueprint grid shrink on phones */
  body {
    background-size: 24px 24px;
  }
  
  .header-container {
    padding: 10px 16px;
  }
  
  .logo-img {
    height: 38px;
  }

  .main-content {
    padding: 16px 12px; /* Super small viewport margin */
  }

  .card-container {
    padding: 20px 16px; /* Utilize maximum card width */
    border-radius: var(--border-radius-md);
  }

  .badge {
    padding: 4px 12px;
    font-size: 10px;
  }

  .experiment-title {
    font-size: 24px; /* Scaled title text */
    margin-bottom: 12px;
  }

  .manual-container {
    margin-bottom: 24px;
  }
  
  .btn {
    padding: 12px 20px;
    font-size: 14px;
    width: 100%; /* Full-width manual links on phone */
  }

  /* Stack button blocks vertically for easy tapping */
  .buttons-grid {
    grid-template-columns: 1fr; 
    gap: 12px;
    margin-bottom: 24px;
  }

  .tab-button {
    padding: 14px 16px;
    border-radius: var(--border-radius-md);
    width: 100%;
    min-height: 54px; /* Touch target guidance */
  }

  .tab-button-icon {
    width: 38px;
    height: 38px;
  }
  
  .tab-button-icon svg {
    width: 18px;
    height: 18px;
  }

  .tab-title {
    font-size: 15px;
  }

  /* Accordion optimization for phones */
  .accordion-box.expanded {
    margin-bottom: 16px;
  }

  .accordion-inner {
    padding: 0 12px 16px; /* Tighter padding inside video accordion */
  }

  .accordion-box.expanded .accordion-inner {
    padding-top: 16px;
  }
  
  .video-container {
    margin-bottom: 12px;
    border-radius: var(--border-radius-sm);
  }
  
  /* Science icons smaller and less visible on mobile to keep focus */
  .float-icon {
    width: 44px;
    height: 44px;
  }
}