/* Bobby Fischer Teaches Chess - Web Application Stylesheet */

:root {
  --bg-primary: #181c20;
  --bg-secondary: #22272e;
  --bg-card: #2a313c;
  --bg-accent: #333c48;
  --text-main: #f0f3f6;
  --text-muted: #959da5;
  --text-highlight: #ffdf7d;
  --accent-fischer: #d4a373;
  --board-light: #f0d9b5;
  --board-dark: #b58863;
  --board-border: #443224;
  --square-selected: rgba(20, 130, 230, 0.5);
  --square-hint: rgba(255, 215, 0, 0.4);
  --square-last-move: rgba(155, 199, 0, 0.41);
  --success-color: #2ea043;
  --success-bg: rgba(46, 160, 67, 0.15);
  --error-color: #f85149;
  --error-bg: rgba(248, 81, 73, 0.15);
  --border-radius: 8px;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--bg-accent);
  padding: 12px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-area h1 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--accent-fischer);
}

.badge-dos {
  background-color: #8b5cf6;
  color: #fff;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  text-transform: uppercase;
}

.header-stats {
  display: flex;
  gap: 16px;
  align-items: center;
  font-size: 0.9rem;
}

.stat-pill {
  background-color: var(--bg-card);
  padding: 6px 14px;
  border-radius: 20px;
  border: 1px solid var(--bg-accent);
  display: flex;
  gap: 6px;
}

.stat-pill strong {
  color: var(--text-highlight);
}

/* Main Container Layout */
.app-container {
  display: flex;
  flex: 1;
  max-width: 1440px;
  margin: 0 auto;
  width: 100%;
  padding: 20px;
  gap: 24px;
}

/* Sidebar for Chapter Navigation */
.sidebar {
  width: 320px;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius);
  border: 1px solid var(--bg-accent);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-header {
  padding: 16px;
  border-bottom: 1px solid var(--bg-accent);
  background-color: var(--bg-card);
}

.sidebar-header h2 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent-fischer);
  margin-bottom: 8px;
}

.chapter-selector {
  width: 100%;
  background-color: var(--bg-secondary);
  color: var(--text-main);
  border: 1px solid var(--bg-accent);
  border-radius: 6px;
  padding: 8px 12px;
  font-size: 0.9rem;
  cursor: pointer;
  outline: none;
}

.steps-list {
  flex: 1;
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  max-height: calc(100vh - 200px);
}

.step-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background-color: #242b35;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
  border: 1px solid #364150;
  font-size: 0.92rem;
  color: #f0f6fc;
}

.step-item:hover {
  background-color: #2f3846;
  border-color: var(--accent-fischer);
  transform: translateX(2px);
}

.step-item.active {
  border-color: var(--accent-fischer);
  background-color: #2d3744;
  box-shadow: inset 4px 0 0 var(--accent-fischer);
  font-weight: 600;
}

.step-item.completed {
  border-left: 4px solid var(--success-color);
}

.step-title {
  color: #f0f6fc;
  font-weight: 500;
}

.step-status {
  font-size: 0.8rem;
  font-weight: 500;
  color: #9aa5b1;
}

.step-item.completed .step-status {
  color: #3fb950;
  font-weight: 600;
}

/* Center Stage - Chessboard and Workspace */
.main-stage {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.lesson-meta-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--bg-secondary);
  padding: 12px 20px;
  border-radius: var(--border-radius);
  border: 1px solid var(--bg-accent);
}

.meta-title h3 {
  font-size: 1.15rem;
  font-weight: 600;
}

.meta-step-count {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.meta-turn-indicator {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 16px;
  background-color: var(--bg-card);
  border: 1px solid var(--bg-accent);
}

.turn-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
}

.turn-dot.white {
  background-color: #fff;
  border: 1px solid #333;
}

.turn-dot.black {
  background-color: #111;
  border: 1px solid #777;
}

/* Board and Feedback Layout */
.interactive-workspace {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 24px;
}

/* Chessboard Component */
.board-wrapper {
  background-color: var(--board-border);
  padding: 12px;
  border-radius: 10px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
  display: inline-block;
  user-select: none;
}

.chessboard {
  display: grid;
  grid-template-columns: repeat(8, 64px);
  grid-template-rows: repeat(8, 64px);
  border: 2px solid var(--board-border);
  position: relative;
}

.board-arrows-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 512px;
  height: 512px;
  pointer-events: none;
  z-index: 10;
}

.square {
  width: 64px;
  height: 64px;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  cursor: pointer;
}

.square.light {
  background-color: var(--board-light);
}

.square.dark {
  background-color: var(--board-dark);
}

.square.selected {
  background-color: var(--square-selected) !important;
}

.square.last-move {
  background-color: var(--square-last-move) !important;
}

.square.hint-target::after {
  content: "";
  width: 22px;
  height: 22px;
  background-color: rgba(20, 130, 230, 0.45);
  border-radius: 50%;
  position: absolute;
}

.square-coord {
  position: absolute;
  font-size: 10px;
  font-weight: 700;
  pointer-events: none;
  line-height: 1;
}

.square-coord.rank {
  top: 3px;
  left: 3px;
}

.square-coord.file {
  bottom: 3px;
  right: 3px;
}

.square.light .square-coord {
  color: var(--board-dark);
}

.square.dark .square-coord {
  color: var(--board-light);
}

.piece {
  width: 58px;
  height: 58px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: grab;
  z-index: 2;
  transition: transform 0.1s ease;
  filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.5));
}

.piece svg {
  width: 100%;
  height: 100%;
  display: block;
}

.piece:active {
  cursor: grabbing;
  transform: scale(1.08);
}

/* Theory Card (Non-board instructional frames) */
/* Theory Card (Center container exclusively for visual diagrams & UI mockups) */
.theory-card {
  width: 536px;
  height: 536px;
  background: radial-gradient(circle at center, #2e3540 0%, #1f252e 100%);
  border-radius: var(--border-radius);
  border: 2px solid var(--accent-fischer);
  padding: 32px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  gap: 24px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

.theory-asset-illustration {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.points-badge-diagram {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  background: radial-gradient(circle, #e63946 0%, #b71c1c 70%, #7f0000 100%);
  border: 4px solid #ffdf7d;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.5), inset 0 2px 8px rgba(255, 255, 255, 0.3);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  color: #fff;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.points-badge-number {
  font-size: 2.75rem;
  line-height: 1;
  color: #fffae6;
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.6);
}

.points-badge-label {
  font-size: 0.85rem;
  color: #ffd700;
  font-weight: 700;
  margin-top: 2px;
}

.theory-card h4 {
  font-size: 1.35rem;
  color: var(--accent-fischer);
  font-weight: 700;
  letter-spacing: 0.5px;
}

.theory-card .diagram-caption {
  font-size: 0.95rem;
  color: #9aa5b1;
  max-width: 380px;
}

/* Pedagogical Feedback & Action Panel */
.pedagogy-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.prompt-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--bg-accent);
  border-radius: var(--border-radius);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.prompt-card h4 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--accent-fischer);
}

.prompt-text {
  font-size: 1.05rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  overflow-wrap: break-word;
  max-width: 680px;
  color: var(--text-main);
}

/* Multiple-Choice Action Buttons */
.choices-container {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 8px;
}

.choice-btn {
  background-color: var(--bg-card);
  border: 1px solid var(--bg-accent);
  color: var(--text-main);
  padding: 12px 18px;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  text-align: left;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 12px;
}

.choice-btn:hover {
  background-color: var(--bg-accent);
  border-color: var(--accent-fischer);
}

.choice-letter {
  display: inline-flex;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background-color: var(--bg-secondary);
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--accent-fischer);
}

/* Feedback Response Banner */
.feedback-card {
  border-radius: var(--border-radius);
  padding: 18px 20px;
  display: none;
  flex-direction: column;
  gap: 8px;
  animation: fadeIn 0.25s ease-out;
}

.feedback-card.visible {
  display: flex;
}

.feedback-card.success {
  background-color: var(--success-bg);
  border: 1px solid var(--success-color);
}

.feedback-card.error {
  background-color: var(--error-bg);
  border: 1px solid var(--error-color);
}

.feedback-header {
  font-weight: 700;
  font-size: 1.05rem;
  display: flex;
  align-items: center;
  gap: 8px;
}

.feedback-card.success .feedback-header {
  color: var(--success-color);
}

.feedback-card.error .feedback-header {
  color: var(--error-color);
}

.feedback-body {
  font-size: 0.95rem;
  line-height: 1.5;
  white-space: pre-wrap;
}

/* Navigation & Controls */
.controls-bar {
  display: flex;
  gap: 12px;
  margin-top: auto;
}

.btn {
  padding: 10px 20px;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-secondary {
  background-color: var(--bg-card);
  color: var(--text-main);
  border: 1px solid var(--bg-accent);
}

.btn-secondary:hover {
  background-color: var(--bg-accent);
}

.btn-primary {
  background-color: var(--accent-fischer);
  color: #1a1a1a;
}

.btn-primary:hover {
  background-color: #e5b383;
}

.btn-success {
  background-color: var(--success-color);
  color: #fff;
}

.btn-success:hover {
  background-color: #38b64e;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Breakpoints */
@media (max-width: 1080px) {
  .interactive-workspace {
    grid-template-columns: 1fr;
    justify-items: center;
  }
  .app-container {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
  }
  .steps-list {
    max-height: 160px;
  }
}