/* ============================================
   SURVIVAL MATH GAME - DESIGN SYSTEM
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@400;600;700;800&family=Inter:wght@400;500;600&display=swap');

/* ============================================
   CSS VARIABLES - DESIGN TOKENS
   ============================================ */

:root {
  /* Color Palette - Vibrant Dark Theme */
  --color-bg-primary: #0a0e27;
  --color-bg-secondary: #151b3d;
  --color-bg-tertiary: #1e2749;
  
  /* Vibrant Accents */
  --color-accent-primary: #ff6b35;
  --color-accent-secondary: #f7931e;
  --color-accent-glow: rgba(255, 107, 53, 0.4);
  
  /* Game Colors */
  --color-player: #4ecdc4;
  --color-enemy: #ff4757;
  --color-health: #ee5a6f;
  --color-xp: #ffd93d;
  
  /* UI Colors */
  --color-success: #6bcf7f;
  --color-warning: #f7931e;
  --color-error: #ff4757;
  
  /* Text Colors */
  --color-text-primary: #ffffff;
  --color-text-secondary: #b8c5d6;
  --color-text-muted: #7a8ba3;
  
  /* Glassmorphism */
  --glass-bg: rgba(30, 39, 73, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
  --glass-blur: blur(12px);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 30px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
  
  /* Typography */
  --font-display: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */

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

body {
  font-family: var(--font-body);
  background: linear-gradient(135deg, var(--color-bg-primary) 0%, var(--color-bg-secondary) 100%);
  color: var(--color-text-primary);
  min-height: 100vh;
  overflow: hidden;
  position: relative;
}

/* Animated Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: 
    radial-gradient(circle at 20% 50%, rgba(255, 107, 53, 0.1) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(78, 205, 196, 0.1) 0%, transparent 50%);
  animation: backgroundPulse 8s ease-in-out infinite;
  pointer-events: none;
  z-index: 0;
}

@keyframes backgroundPulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 0.8; }
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.2;
}

h1 {
  font-size: 3.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-shadow: 0 0 30px var(--color-accent-glow);
}

h2 {
  font-size: 2rem;
  margin-bottom: var(--spacing-md);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--spacing-sm);
}

p {
  line-height: 1.6;
  color: var(--color-text-secondary);
}

/* ============================================
   GLASS PANEL COMPONENT
   ============================================ */

.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--glass-shadow);
  padding: var(--spacing-lg);
  position: relative;
  overflow: hidden;
}

.glass-panel::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  padding: var(--spacing-sm) var(--spacing-lg);
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
  overflow: hidden;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-secondary));
  color: white;
  box-shadow: 0 4px 15px var(--color-accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--color-accent-glow);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: var(--glass-bg);
  border: 2px solid var(--glass-border);
  color: var(--color-text-primary);
  backdrop-filter: var(--glass-blur);
}

.btn-secondary:hover {
  border-color: var(--color-accent-primary);
  background: rgba(255, 107, 53, 0.1);
}

.btn-large {
  font-size: 1.25rem;
  padding: var(--spacing-md) var(--spacing-xl);
}

/* Button Ripple Effect */
.btn::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.3);
  transform: translate(-50%, -50%);
  transition: width 0.6s, height 0.6s;
}

.btn:active::after {
  width: 300px;
  height: 300px;
}

/* ============================================
   LAYOUT CONTAINERS
   ============================================ */

.container {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-lg);
}

.screen {
  display: none;
  width: 100%;
  max-width: 1400px;
  animation: fadeIn var(--transition-slow);
}

.screen.active {
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* ============================================
   HERO SPLASH SCREEN
   ============================================ */

.hero-splash {
  justify-content: center;
  text-align: center;
  overflow-x: hidden;
  overflow-y: auto;
  position: relative;
  width: 100%;
  max-height: 100%;
  padding: 0.75rem 0;
}

.hero-splash-glow {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 30% 20%, rgba(255, 107, 53, 0.3), transparent 38%),
    radial-gradient(circle at 70% 30%, rgba(78, 205, 196, 0.28), transparent 35%),
    radial-gradient(circle at 50% 80%, rgba(247, 147, 30, 0.3), transparent 42%);
  pointer-events: none;
}

.hero-splash-content {
  position: relative;
  max-width: 760px;
  z-index: 1;
}

.hero-kicker {
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-weight: 700;
  color: var(--color-player);
}

.hero-title {
  margin: var(--spacing-xs) 0 var(--spacing-sm);
  font-size: clamp(3.2rem, 11vw, 8rem);
  line-height: 0.95;
  text-shadow: 0 0 40px var(--color-accent-glow);
}

.hero-subtitle {
  font-size: clamp(1rem, 2.6vw, 1.4rem);
  width: min(92vw, 620px);
  margin: 0 auto var(--spacing-md);
  color: var(--color-text-primary);
}

.how-to-panel {
  margin: 0 auto var(--spacing-lg);
  width: min(92vw, 560px);
  background: rgba(8, 14, 35, 0.55);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  text-align: left;
}

.how-to-panel h3 {
  margin: 0 0 0.35rem;
  font-size: 1.05rem;
}

.how-to-panel p {
  margin: 0.16rem 0;
  font-size: 0.93rem;
  color: var(--color-text-secondary);
}

.how-to-panel .best-wave {
  margin-top: 0.45rem;
  color: var(--color-text-primary);
  font-weight: 700;
}

@keyframes fadeIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

/* ============================================
   CHARACTER SELECTION
   ============================================ */

#character-selection {
  text-align: center;
}

.character-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
  width: 100%;
}

.character-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  border: 2px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  position: relative;
}

.character-card:hover {
  transform: translateY(-8px);
  border-color: var(--color-accent-primary);
  box-shadow: 0 12px 40px var(--color-accent-glow);
}

.character-card.selected {
  border-color: var(--color-accent-primary);
  background: rgba(255, 107, 53, 0.15);
  box-shadow: 0 0 30px var(--color-accent-glow);
}

.character-icon {
  width: 120px;
  height: 120px;
  margin: 0 auto var(--spacing-md);
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-player));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
}

.character-name {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
}

.character-stats {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-md);
  text-align: left;
}

.stat-bar {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.stat-label {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  min-width: 80px;
}

.stat-fill {
  flex: 1;
  height: 8px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
  overflow: hidden;
}

.stat-fill-inner {
  height: 100%;
  background: linear-gradient(90deg, var(--color-accent-primary), var(--color-accent-secondary));
  border-radius: 4px;
  transition: width var(--transition-normal);
}

/* ============================================
   AGE SELECTION
   ============================================ */

#age-selection {
  text-align: center;
}

.age-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
  margin: var(--spacing-xl) 0;
  width: 100%;
  max-width: 900px;
}

.age-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  border: 2px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
}

.age-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-accent-secondary);
  box-shadow: 0 8px 25px rgba(247, 147, 30, 0.3);
}

.age-card.selected {
  border-color: var(--color-accent-secondary);
  background: rgba(247, 147, 30, 0.15);
}

.age-year {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-accent-secondary);
  margin-bottom: var(--spacing-xs);
}

.age-range {
  font-size: 1rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-sm);
}

.age-focus {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  font-style: italic;
}

/* ============================================
   GAME CANVAS
   ============================================ */

#game-screen {
  width: 100%;
  height: 100vh;
  padding: 0;
  max-width: none;
}

#game-canvas {
  display: block;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at center, #1a1f3a 0%, #0a0e27 100%);
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}

/* ============================================
   GAME UI OVERLAY
   ============================================ */

.game-ui {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 10;
}

.game-hud {
  position: absolute;
  top: var(--spacing-lg);
  left: var(--spacing-lg);
  right: var(--spacing-lg);
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: var(--spacing-md);
  pointer-events: none;
}

.hud-panel {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  min-width: 0;
}

.hud-label {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 4px;
}

.hud-value {
  font-size: 1.25rem;
  font-weight: 700;
  font-family: var(--font-display);
}

.health-bar, .xp-bar {
  height: 12px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 6px;
  overflow: hidden;
  margin-top: var(--spacing-xs);
}

.health-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-health), #ff6b9d);
  border-radius: 6px;
  transition: width var(--transition-fast);
  box-shadow: 0 0 10px var(--color-health);
}

.xp-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-xp), #ffa500);
  border-radius: 6px;
  transition: width var(--transition-fast);
  box-shadow: 0 0 10px var(--color-xp);
}

/* ============================================
   TOUCH CONTROLS
   ============================================ */

.touch-controls {
  display: none;
}

@media (pointer: coarse), (max-width: 900px) {
  .touch-controls {
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
    position: absolute;
    left: 0;
    right: 0;
    bottom: max(12px, env(safe-area-inset-bottom));
    padding: 0 var(--spacing-md);
    pointer-events: none;
    z-index: 12;
  }

  .touch-dpad,
  .touch-actions {
    pointer-events: auto;
  }

  .touch-dpad {
    width: 180px;
    height: 180px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    gap: 0.45rem;
    grid-template-areas:
      ". up ."
      "left . right"
      ". down .";
  }

  .touch-actions {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    width: min(42vw, 200px);
  }

  .touch-btn {
    border: 1px solid rgba(255, 255, 255, 0.25);
    border-radius: 14px;
    background: rgba(8, 15, 30, 0.72);
    color: #fff;
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 700;
    min-height: 52px;
    touch-action: none;
    user-select: none;
  }

  .touch-btn:active {
    transform: scale(0.96);
    background: rgba(255, 107, 53, 0.55);
  }

  .touch-btn.up { grid-area: up; }
  .touch-btn.left { grid-area: left; }
  .touch-btn.right { grid-area: right; }
  .touch-btn.down { grid-area: down; }
  .touch-btn.attack { min-height: 62px; font-size: 1.05rem; }
}

/* ============================================
   MATH MODAL
   ============================================ */

.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(8px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 100;
  pointer-events: all;
  animation: fadeIn var(--transition-normal);
}

.modal-overlay.active {
  display: flex;
}

.modal-content {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  border: 2px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  max-width: 600px;
  width: 90%;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
  animation: slideUp var(--transition-normal);
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

.modal-header {
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

.question-text {
  font-size: 2rem;
  font-weight: 700;
  font-family: var(--font-display);
  color: var(--color-text-primary);
  margin: var(--spacing-lg) 0;
  text-align: center;
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-md);
}

.answer-input {
  width: 100%;
  font-size: 1.5rem;
  font-family: var(--font-display);
  font-weight: 600;
  padding: var(--spacing-md);
  background: rgba(255, 255, 255, 0.05);
  border: 2px solid var(--glass-border);
  border-radius: var(--radius-md);
  color: var(--color-text-primary);
  text-align: center;
  transition: all var(--transition-normal);
  margin-bottom: var(--spacing-md);
}

.answer-input:focus {
  outline: none;
  border-color: var(--color-accent-primary);
  box-shadow: 0 0 20px var(--color-accent-glow);
}

.modal-buttons {
  display: flex;
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.modal-buttons .btn {
  flex: 1;
}

/* ============================================
   UPGRADE SELECTION
   ============================================ */

.upgrade-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.upgrade-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  border: 2px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  cursor: pointer;
  transition: all var(--transition-normal);
  text-align: center;
}

.upgrade-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-success);
  box-shadow: 0 8px 25px rgba(107, 207, 127, 0.3);
}

.upgrade-card.bonus {
  border-color: var(--color-accent-secondary);
  background: rgba(247, 147, 30, 0.1);
}

.upgrade-card.bonus:hover {
  border-color: var(--color-accent-primary);
  box-shadow: 0 8px 25px var(--color-accent-glow);
}

.upgrade-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-sm);
}

.upgrade-name {
  font-size: 1.125rem;
  font-weight: 700;
  margin-bottom: var(--spacing-xs);
}

.upgrade-description {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.upgrade-bonus-badge {
  display: inline-block;
  background: linear-gradient(135deg, var(--color-accent-primary), var(--color-accent-secondary));
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 12px;
  margin-top: var(--spacing-xs);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

.text-center { text-align: center; }
.text-muted { color: var(--color-text-muted); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }

.hidden { display: none !important; }

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 1100px) {
  .game-hud {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.55rem;
  }

  .hud-panel {
    padding: 0.5rem 0.65rem;
  }
}

@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 1.5rem; }
  
  .character-grid,
  .age-grid {
    grid-template-columns: 1fr;
  }
  
  .game-hud {
    top: 0.55rem;
    left: 0.55rem;
    right: 0.55rem;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.45rem;
  }

  .hud-panel {
    padding: 0.42rem 0.55rem;
  }

  .hud-label {
    font-size: 0.62rem;
    margin-bottom: 2px;
  }

  .hud-value {
    font-size: 0.95rem;
  }

  .health-bar, .xp-bar {
    height: 8px;
    margin-top: 0.3rem;
  }

  .modal-content {
    padding: var(--spacing-lg);
  }
  
  .question-text {
    font-size: 1.5rem;
  }

  .touch-dpad {
    width: 154px;
    height: 154px;
  }

  .touch-actions {
    width: min(44vw, 176px);
  }

  .touch-btn {
    min-height: 46px;
    font-size: 0.93rem;
  }
}

@media (max-height: 700px) {
  .hero-splash {
    justify-content: flex-start;
    padding: 0.45rem 0 0.75rem;
  }

  .hero-splash-content {
    width: min(95vw, 680px);
  }

  .hero-kicker {
    font-size: 0.76rem;
  }

  .hero-title {
    font-size: clamp(2.05rem, 7.3vw, 3.55rem);
    margin: 0.2rem 0 0.32rem;
  }

  .hero-subtitle {
    font-size: 0.9rem;
    margin-bottom: 0.45rem;
  }

  .how-to-panel {
    margin-bottom: 0.55rem;
    padding: 0.5rem 0.62rem;
  }

  .how-to-panel h3 {
    font-size: 0.9rem;
    margin-bottom: 0.22rem;
  }

  .how-to-panel p {
    font-size: 0.8rem;
    margin: 0.08rem 0;
  }

  #enter-hero-battle-btn {
    font-size: 0.98rem;
    padding: 0.68rem 1rem;
  }

  .game-hud {
    top: 0.35rem;
    left: 0.4rem;
    right: 0.4rem;
    gap: 0.35rem;
  }

  .hud-panel {
    padding: 0.33rem 0.45rem;
  }

  .hud-label {
    font-size: 0.56rem;
    margin-bottom: 1px;
  }

  .hud-value {
    font-size: 0.82rem;
  }

  .health-bar, .xp-bar {
    height: 6px;
    margin-top: 0.22rem;
  }

  .touch-dpad {
    width: 132px;
    height: 132px;
  }

  .touch-actions {
    width: min(42vw, 150px);
  }
}