/* ==========================================================================
   ApfelTastaturLernen - Premium Glassmorphic Keyboard Trainer Stylesheet
   ========================================================================== */

/* --- Design Tokens --- */
:root {
  /* Color Palette (HSL) */
  --bg-app: hsl(222, 28%, 7%);
  --bg-glass: hsla(223, 20%, 12%, 0.55);
  --bg-glass-hover: hsla(223, 20%, 18%, 0.7);
  --bg-key: hsl(224, 18%, 15%);
  --bg-key-hover: hsl(224, 18%, 20%);
  --bg-key-modifier: hsl(224, 15%, 11%);
  
  --border-glass: hsla(223, 20%, 30%, 0.25);
  --border-glass-highlight: hsla(223, 20%, 40%, 0.4);
  
  --text-main: hsl(220, 20%, 95%);
  --text-muted: hsl(220, 10%, 65%);
  --text-dark: hsl(220, 20%, 15%);
  
  /* Accent Colors */
  --accent-cyan: hsl(182, 85%, 50%);
  --accent-cyan-glow: hsla(182, 85%, 50%, 0.4);
  --accent-purple: hsl(272, 85%, 60%);
  --accent-purple-glow: hsla(272, 85%, 60%, 0.4);
  --accent-green: hsl(145, 80%, 45%);
  --accent-green-glow: hsla(145, 80%, 45%, 0.4);
  --accent-amber: hsl(38, 95%, 55%);
  --accent-amber-glow: hsla(38, 95%, 55%, 0.4);
  
  /* Dimensions & Spacing */
  --key-size: 54px;
  --key-gap: 6px;
  --border-radius-sm: 6px;
  --border-radius-md: 12px;
  --border-radius-lg: 24px;
  
  /* Transitions */
  --trans-fast: 0.15s ease;
  --trans-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- Base Reset & Typography --- */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  user-select: none;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-app);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 10% 20%, hsla(272, 85%, 45%, 0.1) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, hsla(182, 85%, 45%, 0.1) 0%, transparent 40%);
}

.font-code {
  font-family: "SF Mono", Menlo, Monaco, Consolas, monospace;
}

/* --- Layout Container --- */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px;
  width: 100%;
}

/* --- Header Section --- */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding: 16px 24px;
  border-radius: var(--border-radius-md);
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-glass);
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 16px;
}

.logo-icon {
  font-size: 32px;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 10px var(--accent-cyan-glow));
}

.logo-text h1 {
  font-size: 24px;
  font-weight: 700;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, var(--text-main), var(--text-muted));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.logo-text p {
  font-size: 13px;
  color: var(--text-muted);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

.layout-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: hsla(220, 20%, 30%, 0.2);
  border: 1px solid var(--border-glass);
  border-radius: var(--border-radius-sm);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-muted);
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--accent-cyan);
  box-shadow: 0 0 8px var(--accent-cyan);
}

/* --- Common UI Components --- */
.glass {
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-glass);
  border-radius: var(--border-radius-lg);
  box-shadow: 0 20px 45px rgba(0, 0, 0, 0.35);
  transition: border var(--trans-normal);
}

.glass-premium {
  background: linear-gradient(135deg, hsla(223, 25%, 15%, 0.7) 0%, hsla(223, 25%, 10%, 0.7) 100%);
  border: 1px solid var(--border-glass-highlight);
  border-radius: var(--border-radius-md);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
}

/* Button & Icon Styles */
.icon-btn {
  background: hsla(220, 20%, 30%, 0.15);
  border: 1px solid var(--border-glass);
  color: var(--text-muted);
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--trans-fast);
}

.icon-btn:hover {
  background: hsla(220, 20%, 30%, 0.3);
  color: var(--text-main);
  border-color: var(--border-glass-highlight);
  transform: translateY(-2px);
}

/* --- Main App Grid --- */
.app-main {
  display: grid;
  grid-template-columns: 420px 1fr;
  gap: 24px;
  flex: 1;
  align-items: start;
}

/* --- Left Column: Control Panel --- */
.control-panel {
  display: flex;
  flex-direction: column;
  height: calc(100vh - 160px);
  min-height: 580px;
  overflow: hidden;
  padding: 24px;
}

/* Tabs */
.tab-container {
  display: flex;
  gap: 8px;
  background: hsla(220, 25%, 5%, 0.4);
  padding: 4px;
  border-radius: var(--border-radius-md);
  margin-bottom: 20px;
  border: 1px solid var(--border-glass);
}

.tab-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  padding: 10px 16px;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--trans-normal);
}

.tab-btn.active {
  background: hsla(220, 20%, 25%, 0.6);
  color: var(--text-main);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.tab-content {
  display: none;
  flex-direction: column;
  flex: 1;
  overflow: hidden;
}

.tab-content.active {
  display: flex;
}

/* --- Lookup Mode UI --- */
.filter-bar {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.filter-btn {
  background: hsla(220, 20%, 20%, 0.35);
  border: 1px solid var(--border-glass);
  color: var(--text-muted);
  font-family: inherit;
  font-size: 11px;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 20px;
  cursor: pointer;
  transition: all var(--trans-fast);
}

.filter-btn:hover {
  border-color: var(--border-glass-highlight);
  color: var(--text-main);
}

.filter-btn.active {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  color: var(--text-dark);
  border-color: transparent;
  font-weight: 700;
  box-shadow: 0 4px 10px var(--accent-cyan-glow);
}

.symbols-grid-container {
  flex: 1;
  overflow-y: auto;
  padding-right: 4px;
}

/* Custom Scrollbar */
.symbols-grid-container::-webkit-scrollbar {
  width: 6px;
}
.symbols-grid-container::-webkit-scrollbar-track {
  background: transparent;
}
.symbols-grid-container::-webkit-scrollbar-thumb {
  background: var(--border-glass);
  border-radius: 3px;
}
.symbols-grid-container::-webkit-scrollbar-thumb:hover {
  background: var(--border-glass-highlight);
}

.symbols-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
  gap: 10px;
}

.symbol-card {
  aspect-ratio: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border-radius: var(--border-radius-md);
  background: hsla(220, 20%, 20%, 0.25);
  border: 1px solid var(--border-glass);
  cursor: pointer;
  transition: all var(--trans-normal);
  position: relative;
  overflow: hidden;
}

.symbol-card:hover {
  transform: translateY(-3px);
  background: hsla(220, 20%, 30%, 0.35);
  border-color: var(--accent-cyan);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3), 0 0 8px var(--accent-cyan-glow);
}

.symbol-card.active {
  background: hsla(182, 85%, 50%, 0.1);
  border-color: var(--accent-cyan);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4), 0 0 15px var(--accent-cyan-glow);
}

.symbol-card-char {
  font-family: 'JetBrains Mono', monospace;
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 4px;
  color: var(--text-main);
  transition: color var(--trans-fast);
}

.symbol-card.active .symbol-card-char {
  color: var(--accent-cyan);
  text-shadow: 0 0 10px var(--accent-cyan-glow);
}

.symbol-card-name {
  font-size: 10px;
  color: var(--text-muted);
  text-align: center;
  padding: 0 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  width: 100%;
}

/* --- Quiz Mode UI --- */
.quiz-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-bottom: 12px;
}

.stat-card {
  display: flex;
  flex-direction: column;
  background: hsla(220, 20%, 20%, 0.3);
  border: 1px solid var(--border-glass);
  padding: 8px 12px;
  border-radius: var(--border-radius-md);
  text-align: center;
  position: relative;
}

.stat-label {
  font-size: 11px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

.stat-value {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-main);
}

.streak-fire {
  position: absolute;
  top: 4px;
  right: 8px;
  font-size: 14px;
  opacity: 0;
  transform: scale(0.5);
  transition: all var(--trans-normal);
}

#quiz-streak:not(:empty) + .streak-fire {
  /* Visible if streak > 0, controlled by JS class */
}
.streak-active .streak-fire {
  opacity: 1;
  transform: scale(1);
  animation: pulse-fire 1.5s infinite alternate;
}

@keyframes pulse-fire {
  0% { transform: scale(1); filter: drop-shadow(0 0 2px orange); }
  100% { transform: scale(1.15); filter: drop-shadow(0 0 8px red); }
}

.progress-bar-container {
  height: 6px;
  background: hsla(220, 25%, 5%, 0.5);
  border-radius: 3px;
  overflow: hidden;
  margin-bottom: 20px;
  border: 1px solid var(--border-glass);
}

.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent-purple), var(--accent-cyan));
  box-shadow: 0 0 8px var(--accent-cyan);
  transition: width var(--trans-normal);
}

.quiz-prompt-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px 24px;
  margin-bottom: 20px;
  position: relative;
  text-align: center;
  min-height: 200px;
}

.quiz-instruction {
  font-size: 13px;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.target-char {
  font-family: 'JetBrains Mono', monospace;
  font-size: 80px;
  font-weight: 700;
  margin: 12px 0;
  background: linear-gradient(135deg, var(--text-main) 30%, var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 15px rgba(255, 255, 255, 0.1));
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0% { transform: translateY(0px); }
  50% { transform: translateY(-6px); }
  100% { transform: translateY(0px); }
}

.target-name {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-muted);
}

.quiz-input-preview {
  display: flex;
  align-items: center;
  gap: 12px;
  background: hsla(220, 20%, 5%, 0.4);
  border: 1px solid var(--border-glass);
  padding: 12px 16px;
  border-radius: var(--border-radius-md);
  margin-bottom: 20px;
}

.preview-label {
  font-size: 12px;
  color: var(--text-muted);
}

.user-input-box {
  flex: 1;
  font-size: 20px;
  font-weight: 700;
  color: var(--accent-cyan);
  text-shadow: 0 0 8px var(--accent-cyan-glow);
  min-height: 30px;
  display: flex;
  align-items: center;
}

.quiz-controls {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
}

.action-btn {
  flex: 1;
  padding: 12px 20px;
  border-radius: var(--border-radius-md);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--trans-normal);
}

.hint-btn {
  background: hsla(38, 95%, 55%, 0.15);
  border: 1px solid var(--accent-amber);
  color: var(--accent-amber);
}

.hint-btn:hover {
  background: var(--accent-amber);
  color: var(--text-dark);
  box-shadow: 0 4px 15px var(--accent-amber-glow);
}

.skip-btn {
  background: hsla(220, 20%, 30%, 0.2);
  border: 1px solid var(--border-glass);
  color: var(--text-muted);
}

.skip-btn:hover {
  background: hsla(220, 20%, 30%, 0.4);
  color: var(--text-main);
  border-color: var(--border-glass-highlight);
}

.hint-box {
  background: hsla(38, 95%, 55%, 0.1);
  border-left: 4px solid var(--accent-amber);
  padding: 12px 16px;
  border-radius: 0 var(--border-radius-md) var(--border-radius-md) 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: all var(--trans-normal);
  opacity: 1;
}

.hint-box.hidden {
  opacity: 0;
  max-height: 0;
  padding: 0;
  margin: 0;
  border: none;
  overflow: hidden;
}

.hint-title {
  font-size: 12px;
  font-weight: 700;
  color: var(--accent-amber);
}

.hint-text {
  font-size: 14px;
  color: var(--text-main);
}

/* Quiz Overlay */
.quiz-start-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(10, 14, 23, 0.85);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--border-radius-lg);
  z-index: 10;
  transition: opacity var(--trans-normal);
}

.quiz-start-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.play-btn {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));
  color: var(--text-dark);
  font-family: inherit;
  font-size: 18px;
  font-weight: 700;
  padding: 16px 36px;
  border: none;
  border-radius: 30px;
  cursor: pointer;
  box-shadow: 0 10px 25px rgba(0,0,0,0.5), 0 0 15px var(--accent-cyan-glow);
  transition: all var(--trans-normal);
}

.play-btn:hover {
  transform: scale(1.05);
  box-shadow: 0 12px 30px rgba(0,0,0,0.6), 0 0 25px var(--accent-cyan-glow);
}

/* --- Right Column: Keyboard Panel --- */
.keyboard-panel {
  display: flex;
  flex-direction: column;
  padding: 24px;
  overflow: hidden;
  height: calc(100vh - 160px);
  min-height: 580px;
}

.keyboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-glass);
}

.keyboard-legend {
  display: flex;
  gap: 16px;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--text-muted);
}

.legend-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}
.legend-dot.normal { background: var(--bg-key); border: 1px solid var(--border-glass); }
.legend-dot.shift { background: hsla(272, 85%, 60%, 0.2); border: 1px solid var(--accent-purple); }
.legend-dot.option { background: hsla(182, 85%, 50%, 0.2); border: 1px solid var(--accent-cyan); }
.legend-dot.active { background: var(--accent-cyan); box-shadow: 0 0 8px var(--accent-cyan); }

.keyboard-help {
  font-size: 12px;
  color: var(--text-muted);
}
.keyboard-help b {
  color: var(--text-main);
}

.keyboard-wrapper {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  transform-origin: center center;
  transition: transform var(--trans-normal);
  width: 100%;
}

.keyboard-container {
  display: grid;
  grid-template-rows: repeat(6, var(--key-size));
  gap: var(--key-gap);
  padding: 12px;
  background: hsl(224, 25%, 5%);
  border: 1px solid var(--border-glass-highlight);
  border-radius: 16px;
  box-shadow: inset 0 4px 10px rgba(0,0,0,0.8), 0 10px 30px rgba(0,0,0,0.6);
  width: max-content;
}

.keyboard-row {
  display: grid;
  grid-template-columns: repeat(60, calc((var(--key-size) - var(--key-gap) * 3) / 4));
  gap: var(--key-gap);
  width: 100%;
}

/* --- Virtual Key Cap Design --- */
.key {
  background: var(--bg-key);
  border: 1px solid var(--border-glass);
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  position: relative;
  transition: all 0.08s ease;
  box-shadow: 0 3px 0 hsl(224, 18%, 10%), 0 4px 6px rgba(0,0,0,0.4);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 5px 6px;
  color: var(--text-muted);
  box-sizing: border-box;
}

.key:hover {
  background: var(--bg-key-hover);
  border-color: var(--border-glass-highlight);
}

.key:active, .key.pressed {
  background: var(--bg-key);
  transform: translateY(2.5px);
  box-shadow: 0 0.5px 0 hsl(224, 18%, 10%), 0 1px 2px rgba(0,0,0,0.6);
}

/* Modifier Keys */
.key-modifier {
  background: var(--bg-key-modifier);
  font-size: 11px;
  font-weight: 600;
}

/* Label layouts within keys */
.key-label-top-left {
  font-size: 10px;
  align-self: flex-start;
}

.key-label-bottom-left {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-main);
  align-self: flex-start;
}

.key-label-bottom-right {
  position: absolute;
  bottom: 4px;
  right: 5px;
  font-size: 11px;
  font-weight: 600;
  color: var(--accent-cyan);
  opacity: 0.6;
}

.key-label-top-right {
  position: absolute;
  top: 4px;
  right: 5px;
  font-size: 9px;
  color: var(--accent-purple);
  opacity: 0.5;
}

/* Modifier lights for Shift/Option keys */
.key-modifier.active-modifier {
  border-color: var(--accent-purple);
  background: hsla(272, 85%, 60%, 0.15);
  color: var(--text-main);
  box-shadow: 0 0 12px var(--accent-purple-glow);
}

.key-modifier.active-modifier-option {
  border-color: var(--accent-cyan);
  background: hsla(182, 85%, 50%, 0.15);
  color: var(--text-main);
  box-shadow: 0 0 12px var(--accent-cyan-glow);
}

/* Active Highlight (Physically pressed keys or correct key highlighting) */
.key.pressed-glow {
  background: hsla(182, 85%, 50%, 0.2) !important;
  border-color: var(--accent-cyan) !important;
  box-shadow: 0 0 15px var(--accent-cyan-glow), inset 0 0 4px var(--accent-cyan-glow) !important;
  color: var(--text-main) !important;
}

/* Hint state (flashing keys) */
.key.hint-glow {
  animation: pulse-hint 1s infinite alternate;
}

@keyframes pulse-hint {
  0% {
    background: hsla(38, 95%, 55%, 0.1);
    border-color: hsla(38, 95%, 55%, 0.5);
    box-shadow: 0 0 5px hsla(38, 95%, 55%, 0.2);
  }
  100% {
    background: hsla(38, 95%, 55%, 0.35);
    border-color: var(--accent-amber);
    box-shadow: 0 0 15px var(--accent-amber-glow);
  }
}

/* Correct answer state (success flash) */
.key.correct-glow {
  animation: pulse-correct 0.6s 2 alternate;
}

@keyframes pulse-correct {
  0% {
    background: hsla(145, 80%, 45%, 0.1);
    border-color: hsla(145, 80%, 45%, 0.5);
  }
  100% {
    background: hsla(145, 80%, 45%, 0.4);
    border-color: var(--accent-green);
    box-shadow: 0 0 18px var(--accent-green-glow);
  }
}

/* Modifier state layouts: dynamic key cap label highlight */
.show-shift-only .key-label-bottom-left { opacity: 0.3; }
.show-shift-only .key-label-top-left { font-size: 14px; font-weight: 700; color: var(--text-main); }

.show-option-only .key-label-bottom-left { opacity: 0.2; }
.show-option-only .key-label-top-left { opacity: 0.2; }
.show-option-only .key-label-bottom-right { font-size: 15px; font-weight: 700; opacity: 1; text-shadow: 0 0 4px var(--accent-cyan-glow); }

.show-option-shift .key-label-bottom-left { opacity: 0.2; }
.show-option-shift .key-label-top-left { opacity: 0.2; }
.show-option-shift .key-label-top-right { font-size: 14px; font-weight: 700; opacity: 1; text-shadow: 0 0 4px var(--accent-purple-glow); }


/* --- Responsive scaling and transforms --- */
@media (max-width: 1280px) {
  .app-main {
    grid-template-columns: 1fr;
  }
  
  .control-panel {
    height: auto;
    min-height: auto;
  }
  
  .keyboard-panel {
    height: auto;
    min-height: auto;
  }
}

@media (max-width: 900px) {
  body {
    padding: 12px;
  }
  
  .app-container {
    padding: 0;
  }
  
  .app-header {
    flex-direction: column;
    gap: 12px;
    align-items: flex-start;
  }
  
  .keyboard-wrapper {
    overflow-x: auto;
    justify-content: flex-start;
  }
}

/* --- Footer --- */
.app-footer {
  text-align: center;
  padding: 24px;
  color: var(--text-muted);
  font-size: 12px;
  margin-top: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
}

.footer-links {
  display: flex;
  gap: 12px;
  align-items: center;
  font-weight: 500;
}

.footer-link {
  color: var(--text-muted);
  text-decoration: none;
  transition: all var(--trans-fast);
}

.footer-link:hover {
  color: var(--accent-cyan);
  text-shadow: 0 0 4px var(--accent-cyan-glow);
}

.footer-separator {
  color: var(--border-glass);
}

/* Hidden input for dead-key/IME resolution */
.hidden-input {
  position: absolute;
  top: -100px;
  left: -100px;
  width: 1px;
  height: 1px;
  opacity: 0;
  border: none;
  background: transparent;
  pointer-events: none;
  z-index: -1;
}