/* ---------------------------------------------------------------------------
   Design System & Theme Tokens - Alge Algebra Coach (Warm Gold & Amber Theme)
   --------------------------------------------------------------------------- */
:root {
  --bg: #0d0f12;
  --panel-bg: #14171d;
  --panel-border: rgba(255, 255, 255, 0.08);
  --panel-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);

  --card-bg: #1a1e27;
  --card-bg-hover: #222734;
  --card-border: #293040;

  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --text-dim: #6b7280;

  /* Primary Accent: Warm Gold & Amber */
  --accent: #d97706;
  --accent-hover: #b45309;
  --accent-active: #92400e;
  --accent-subtle: rgba(217, 119, 6, 0.15);
  --accent-text: #fcd34d;

  /* Secondary Accent: Soft Emerald for verified/success */
  --secondary: #10b981;
  --secondary-hover: #059669;

  /* Escalating hint stage color */
  --cyan: #38bdf8;

  /* Amber for warning count threshold */
  --amber: #f59e0b;

  /* Rose/Red for incorrect/error states */
  --danger: #ef4444;
  --danger-subtle: rgba(239, 68, 68, 0.12);

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;

  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

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

body {
  background-color: var(--bg);
  color: var(--text-main);
  font-family: var(--font-sans);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---------------------------------------------------------------------------
   App Outer Layout
   --------------------------------------------------------------------------- */
.app {
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px 20px 32px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---------------------------------------------------------------------------
   Header
   --------------------------------------------------------------------------- */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
  padding: 14px 20px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  box-shadow: var(--panel-shadow);
  border-radius: var(--radius-md);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  background: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(217, 119, 6, 0.3);
}

.brand-title-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand h1 {
  font-size: 22px;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.01em;
}

.badge {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: var(--accent-subtle);
  color: var(--accent-text);
  border: 1px solid rgba(252, 211, 77, 0.25);
  padding: 3px 9px;
  border-radius: 20px;
}

.subtitle {
  font-size: 13px;
  color: var(--text-muted);
  margin-top: 2px;
  font-weight: 500;
}

.header-status {
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.25);
  padding: 6px 12px;
  border-radius: 20px;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--secondary);
  box-shadow: 0 0 6px var(--secondary);
}

.status-text {
  font-size: 12px;
  font-weight: 600;
  color: #6ee7b7;
}

/* ---------------------------------------------------------------------------
   Main Layout Grid
   --------------------------------------------------------------------------- */
.layout {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 20px;
  flex: 1;
  min-height: 0;
}

.problem-panel,
.chat-panel {
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  box-shadow: var(--panel-shadow);
  border-radius: var(--radius-lg);
  padding: 22px;
  display: flex;
  flex-direction: column;
}

/* ---------------------------------------------------------------------------
   Left Panel: Problem & Controls
   --------------------------------------------------------------------------- */
.panel-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  color: var(--accent);
}

.panel-header h2 {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.equation-card-container {
  position: relative;
  margin-bottom: 18px;
}

/* Visual Anchor Equation Card - Warm Gold Glow */
.equation-card {
  background: #101319;
  border: 1px solid rgba(217, 119, 6, 0.4);
  border-radius: var(--radius-md);
  padding: 26px 16px;
  font-family: var(--font-mono);
  font-size: 32px;
  font-weight: 700;
  text-align: center;
  color: #ffffff;
  letter-spacing: 0.04em;
  box-shadow: 0 0 22px rgba(217, 119, 6, 0.12), inset 0 1px 3px rgba(0, 0, 0, 0.5);
  transition: all 0.3s ease;
  word-break: break-word;
}

.loading-pulse {
  font-size: 15px;
  font-family: var(--font-sans);
  color: var(--text-muted);
  font-weight: 500;
}

/* Hint Progress Tracker */
.hint-tracker {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  margin-bottom: 14px;
}

.hint-tracker-header {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 8px;
}

.hint-tracker-label {
  color: var(--accent-text);
}

.hint-progress-bar {
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 10px;
  overflow: hidden;
}

.hint-progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 10px;
  transition: width 0.4s ease, background-color 0.4s ease;
}

/* Dynamic Shift as Hints Escalate */
.hint-progress-fill[data-level="1"] {
  background: var(--accent);
}
.hint-progress-fill[data-level="2"] {
  background: var(--cyan);
}
.hint-progress-fill[data-level="3"] {
  background: var(--secondary);
}

/* Metric Cards */
.stats {
  margin-bottom: 18px;
}

.stat-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.stat-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--accent-subtle);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
}

.stat-content {
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
}

.stat-value {
  font-size: 17px;
  font-weight: 700;
  color: var(--text-main);
  margin-top: 1px;
  transition: color 0.3s ease;
}

/* Turns warm amber as it approaches reveal threshold */
.stat-value.attempts-amber {
  color: var(--amber);
}

/* Answer Input Card */
.answer-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 18px;
}

.answer-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.answer-label-row label {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-main);
}

.math-var {
  font-family: var(--font-mono);
  color: var(--accent-text);
  font-weight: 700;
}

.input-hint {
  font-size: 11px;
  color: var(--text-dim);
}

/* Clean Answer Input Wrapping to Prevent Overlaps */
.answer-input-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  background: #0b0d12;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-sm);
  padding: 6px 6px 6px 12px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.answer-input-wrap:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.25);
}

.var-prefix {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  color: var(--accent);
  user-select: none;
  flex-shrink: 0;
}

.answer-input-wrap input {
  flex: 1;
  min-width: 0;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 600;
  outline: none;
  padding: 6px 4px;
}

.btn-check {
  background: var(--accent);
  color: #ffffff;
  border: none;
  border-radius: 6px;
  padding: 9px 16px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn-check:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-check:active:not(:disabled) {
  background: var(--accent-active);
  transform: translateY(0);
}

.btn-check:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* Panel Actions */
.panel-actions {
  display: flex;
  gap: 10px;
}

.btn-secondary {
  flex: 1;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-main);
  border-radius: var(--radius-sm);
  padding: 11px 12px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.2s ease;
}

.btn-secondary:hover:not(:disabled) {
  background: var(--card-bg-hover);
  border-color: rgba(255, 255, 255, 0.18);
  color: #ffffff;
}

.btn-secondary:active:not(:disabled) {
  transform: translateY(1px);
}

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

.hint-note {
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 6px;
  line-height: 1.4;
}

/* ---------------------------------------------------------------------------
   Right Panel: Interactive Coaching Chat
   --------------------------------------------------------------------------- */
.chat-panel {
  min-height: 520px;
}

.chat-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--panel-border);
  margin-bottom: 14px;
}

.coach-avatar {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--accent-subtle);
  border: 1px solid rgba(252, 211, 77, 0.2);
  color: var(--accent-text);
  display: flex;
  align-items: center;
  justify-content: center;
}

.chat-header-text h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-main);
}

.chat-header-sub {
  font-size: 12px;
  color: var(--text-muted);
}

/* Quick Helper Chips with Min 44px Touch Target */
.quick-chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.chip-btn {
  min-height: 44px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 22px;
  color: #d1d5db;
  padding: 8px 16px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

.chip-btn:hover {
  background: var(--accent-subtle);
  border-color: rgba(217, 119, 6, 0.4);
  color: var(--accent-text);
  transform: translateY(-1px);
}

.chip-btn:active {
  background: rgba(217, 119, 6, 0.25);
  transform: scale(0.96);
}

/* Chat Messages Area */
.chat-window {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding-right: 6px;
  margin-bottom: 16px;
  scroll-behavior: smooth;
}

.chat-window::-webkit-scrollbar {
  width: 6px;
}
.chat-window::-webkit-scrollbar-track {
  background: transparent;
}
.chat-window::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 10px;
}

/* Message Items */
.msg-wrapper {
  display: flex;
  gap: 10px;
  max-width: 85%;
}

.msg-wrapper.user {
  align-self: flex-end;
  flex-direction: row-reverse;
}

.msg-wrapper.assistant {
  align-self: flex-start;
}

.msg-avatar {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 700;
  flex-shrink: 0;
}

.msg-wrapper.assistant .msg-avatar {
  background: var(--accent);
  color: #ffffff;
}

.msg-wrapper.user .msg-avatar {
  background: var(--secondary);
  color: #0d0f12;
}

.msg-bubble {
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.msg-wrapper.assistant .msg-bubble {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  color: var(--text-main);
  border-top-left-radius: 4px;
}

.msg-wrapper.user .msg-bubble {
  background: var(--accent);
  color: #ffffff;
  border-top-right-radius: 4px;
}

/* System Notifications */
.msg-system {
  align-self: center;
  max-width: 90%;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 16px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 600;
}

.msg-system.correct {
  background: rgba(16, 185, 129, 0.12);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #6ee7b7;
}

.msg-system.incorrect {
  background: var(--danger-subtle);
  border: 1px solid rgba(239, 68, 68, 0.35);
  color: #fca5a5;
}

.msg-system.solved {
  background: rgba(217, 119, 6, 0.15);
  border: 1px solid rgba(217, 119, 6, 0.35);
  color: #fcd34d;
}

.msg-system.error {
  background: var(--danger-subtle);
  border: 1px solid var(--danger);
  color: var(--danger);
}

/* Chat Input Bar */
.chat-form {
  margin-top: auto;
}

.chat-input-wrapper {
  display: flex;
  align-items: center;
  background: #0d0f12;
  border: 1px solid var(--card-border);
  border-radius: var(--radius-md);
  padding: 6px 6px 6px 14px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.chat-input-wrapper:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(217, 119, 6, 0.25);
}

.chat-input-wrapper input {
  flex: 1;
  min-width: 0;
  background: transparent;
  border: none;
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: 15px;
  outline: none;
  padding: 8px 0;
}

.chat-input-wrapper input::placeholder {
  color: var(--text-dim);
}

.btn-send {
  background: var(--accent);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  padding: 10px 18px;
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn-send:hover:not(:disabled) {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn-send:active:not(:disabled) {
  background: var(--accent-active);
  transform: translateY(0);
}

.btn-send:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.app-footer {
  margin-top: 20px;
  text-align: center;
  font-size: 12px;
  color: var(--text-dim);
}

/* ---------------------------------------------------------------------------
   RESPONSIVENESS BREAKPOINTS
   --------------------------------------------------------------------------- */

@media (max-width: 900px) {
  .app {
    padding: 14px 14px 24px;
  }
  
  .layout {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .problem-panel {
    padding: 18px;
  }

  .chat-panel {
    padding: 18px;
    min-height: 480px;
  }
}

@media (max-width: 480px) {
  .app-header {
    padding: 10px 14px;
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .header-status {
    align-self: flex-start;
  }

  .equation-card {
    font-size: 24px;
    padding: 20px 12px;
  }

  .panel-actions {
    flex-direction: column;
    gap: 8px;
  }

  .answer-input-wrap {
    padding: 6px 6px 6px 10px;
  }

  .answer-input-wrap input,
  .chat-input-wrapper input {
    font-size: 16px !important;
  }

  .quick-chips {
    gap: 6px;
  }

  .chip-btn {
    flex: 1 1 auto;
    text-align: center;
    font-size: 12px;
    min-height: 44px;
  }

  .chat-window {
    height: 48vh;
    max-height: 380px;
    min-height: 240px;
  }
}