/* --- Modern Reset & Base --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg-color: #0b0f19;
  --panel-bg: rgba(15, 23, 42, 0.55);
  --border-color: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(255, 255, 255, 0.15);
  
  --text-main: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --primary: #6366f1; /* Indigo */
  --primary-glow: rgba(99, 102, 241, 0.25);
  --secondary: #a855f7; /* Purple */
  --secondary-glow: rgba(168, 85, 247, 0.2);
  
  --success: #10b981; /* Emerald */
  --success-glow: rgba(16, 185, 129, 0.15);
  --error: #ef4444; /* Rose */
  --error-glow: rgba(239, 68, 68, 0.15);
  --warning: #f59e0b; /* Amber */
  
  --glow-radius: 12px;
  --transition-speed: 0.25s;
}

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  font-family: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
  overflow-x: hidden;
  line-height: 1.5;
}

/* --- Ambient Glow Background --- */
.glow-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  background: 
    radial-gradient(circle at 20% 15%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
    radial-gradient(circle at 80% 80%, rgba(168, 85, 247, 0.12) 0%, transparent 50%),
    radial-gradient(circle at 50% 50%, rgba(15, 23, 42, 0.95) 0%, #060813 100%);
  background-size: cover;
}

/* --- App Container --- */
.app-container {
  width: 100%;
  max-width: 800px;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin: auto;
}

/* --- Header & Stats --- */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo-icon {
  width: 3rem;
  height: 3rem;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.4);
  color: white;
}

.logo-icon svg {
  width: 1.75rem;
  height: 1.75rem;
}

.logo-area h1 {
  font-size: 1.5rem;
  font-weight: 700;
  background: linear-gradient(to right, #ffffff, #d9dcff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.02em;
}

.logo-area .subtitle {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.stats-widget {
  display: flex;
  gap: 1rem;
  background: rgba(15, 23, 42, 0.4);
  padding: 0.5rem;
  border-radius: 14px;
  border: 1px solid var(--border-color);
  backdrop-filter: blur(10px);
}

.stat-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.02);
  min-width: 90px;
}

.stat-icon {
  font-size: 1.25rem;
}

.stat-value-group {
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

.stat-value {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-main);
}

/* --- Glassmorphic Panels --- */
.glass {
  background: var(--panel-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--border-color);
  border-radius: 18px;
  box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
}

/* --- Navigation Tabs --- */
.app-nav {
  display: flex;
  background: rgba(15, 23, 42, 0.4);
  border-radius: 12px;
  padding: 0.35rem;
  border: 1px solid var(--border-color);
  backdrop-filter: blur(8px);
}

.nav-tab {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 0.75rem 1rem;
  font-size: 0.95rem;
  font-weight: 500;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition-speed) ease;
}

.nav-tab svg {
  width: 1.1rem;
  height: 1.1rem;
  stroke-width: 2.2;
}

.nav-tab:hover {
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.03);
}

.nav-tab.active {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.05);
}

/* --- App Content Panes --- */
.app-content {
  min-height: 400px;
}

.tab-pane {
  display: none;
}

.tab-pane.active {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  animation: fadeIn 0.35s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* --- Trainer Mode Selector --- */
.mode-selector {
  display: flex;
  gap: 1rem;
}

.mode-btn {
  flex: 1;
  background: rgba(15, 23, 42, 0.3);
  border: 1px solid var(--border-color);
  padding: 1rem;
  border-radius: 14px;
  cursor: pointer;
  text-align: left;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  transition: all var(--transition-speed) ease;
}

.mode-btn:hover {
  background: rgba(255, 255, 255, 0.02);
  border-color: var(--border-hover);
  transform: translateY(-1px);
}

.mode-btn.active {
  background: radial-gradient(circle at 10% 20%, rgba(99, 102, 241, 0.1) 0%, rgba(15, 23, 42, 0.6) 100%);
  border-color: var(--primary);
  box-shadow: 0 0 15px rgba(99, 102, 241, 0.15);
}

.mode-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text-main);
}

.mode-btn.active .mode-title {
  color: #fff;
}

.mode-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* --- Trainer Card --- */
.trainer-card {
  position: relative;
  overflow: hidden;
}

/* Progress bar / Timer (Optional indicator of speed) */
.timer-bar-container {
  height: 4px;
  background: rgba(255, 255, 255, 0.03);
  width: 100%;
}

.timer-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(to right, var(--primary), var(--secondary));
  transition: width 0.1s linear;
}

.card-body {
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
}

.question-container {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.question-label {
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 500;
}

.question-text {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  background: linear-gradient(135deg, #ffffff 30%, #a5b4fc 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 10px 30px rgba(99, 102, 241, 0.15);
}

.keyboard-tip {
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.keyboard-tip kbd {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 4px;
  padding: 0.1rem 0.35rem;
  box-shadow: 0 1px 0 rgba(0,0,0,0.4);
  font-family: inherit;
  font-weight: 600;
  color: var(--text-secondary);
}

/* Weekday Grid */
.answers-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 0.75rem;
}

.day-btn {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 0.85rem 0.5rem;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  color: var(--text-secondary);
}

.day-btn:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--border-hover);
  color: var(--text-main);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

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

.day-num {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  background: rgba(255, 255, 255, 0.05);
  width: 1.25rem;
  height: 1.25rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.day-name {
  font-size: 0.85rem;
  font-weight: 600;
}

.card-actions {
  display: flex;
  justify-content: center;
  margin-top: 0.5rem;
}

/* Secondary Button style */
.secondary-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.6rem 1.5rem;
  border-radius: 10px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition-speed) ease;
}

.secondary-btn:hover {
  background: rgba(255, 255, 255, 0.03);
  border-color: var(--border-hover);
  color: var(--text-main);
}

/* --- Feedback Panel --- */
.feedback-panel {
  border-radius: 18px;
  overflow: hidden;
  animation: slideDown 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-12px); }
  to { opacity: 1; transform: translateY(0); }
}

.feedback-panel.correct {
  border-left: 4px solid var(--success);
  background: linear-gradient(to right, var(--success-glow), var(--panel-bg));
}

.feedback-panel.incorrect {
  border-left: 4px solid var(--error);
  background: linear-gradient(to right, var(--error-glow), var(--panel-bg));
}

.feedback-header {
  padding: 1.5rem 2.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.feedback-result {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.feedback-icon {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  font-weight: bold;
}

.feedback-panel.correct .feedback-icon {
  background: rgba(16, 185, 129, 0.2);
  color: var(--success);
}
.feedback-panel.correct .feedback-icon::before {
  content: '✓';
}

.feedback-panel.incorrect .feedback-icon {
  background: rgba(239, 68, 68, 0.2);
  color: var(--error);
}
.feedback-panel.incorrect .feedback-icon::before {
  content: '✕';
}

.feedback-text {
  font-size: 1.25rem;
  font-weight: 700;
}

.feedback-panel.correct .feedback-text {
  color: var(--success);
}

.feedback-panel.incorrect .feedback-text {
  color: var(--error);
}

/* Primary Button style */
.primary-btn {
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  border: none;
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 10px;
  cursor: pointer;
  font-size: 0.95rem;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.35);
  transition: all var(--transition-speed) ease;
}

.primary-btn svg {
  width: 1.1rem;
  height: 1.1rem;
  transition: transform 0.2s ease;
}

.primary-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
}

.primary-btn:hover svg {
  transform: translateX(3px);
}

.feedback-details {
  padding: 1.75rem 2.25rem;
}

.details-heading {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-main);
}

.info-icon {
  width: 1.2rem;
  height: 1.2rem;
  color: var(--primary);
}

.explanation-steps {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.step-card {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--border-color);
  padding: 1rem 1.25rem;
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.step-title {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  font-weight: 700;
}

.step-body {
  font-size: 0.95rem;
  color: var(--text-main);
}

.step-body strong {
  color: #fff;
  font-weight: 600;
}

/* Helper Utilities */
.hidden {
  display: none !important;
}

.highlight-pill {
  font-size: 0.75rem;
  background: var(--primary-glow);
  color: var(--primary);
  border: 1px solid rgba(99, 102, 241, 0.3);
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  margin-left: 0.5rem;
  font-weight: 600;
}

/* --- Learn section styles --- */
.learn-container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  padding: 1rem 0;
}

.learn-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.learn-header h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 0.75rem;
}

.learn-intro {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

.learn-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}

.learn-card {
  padding: 2rem;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.learn-card.full-width {
  grid-column: span 2;
}

.learn-card-badge {
  position: absolute;
  top: 1rem;
  right: 1.25rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--secondary);
  background: var(--secondary-glow);
  padding: 0.25rem 0.6rem;
  border-radius: 20px;
}

.learn-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
}

.learn-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.learn-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.learn-list li {
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.learn-list li::before {
  content: "•";
  color: var(--primary);
  font-weight: bold;
  font-size: 1.2rem;
}

.learn-steps-list {
  padding-left: 1.2rem;
  color: var(--text-secondary);
  font-size: 0.95rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.learn-tip {
  background: rgba(245, 158, 11, 0.06);
  border: 1px dashed rgba(245, 158, 11, 0.3);
  padding: 0.85rem 1.1rem;
  border-radius: 10px;
  font-size: 0.85rem;
  color: var(--text-main);
}

.formula-box {
  background: rgba(0, 0, 0, 0.2);
  padding: 0.75rem;
  border-radius: 8px;
  text-align: center;
  font-family: monospace;
  font-size: 0.9rem;
  border: 1px solid rgba(255,255,255,0.04);
}

/* Anchors Visual Grid */
.anchors-grid-visual {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.anchor-month-box {
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0.75rem 0.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
}

.anchor-month-box .m-name {
  font-size: 0.75rem;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--text-muted);
}

.anchor-month-box .m-val {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--primary);
}

.anchor-month-box .m-note {
  font-size: 0.65rem;
  color: var(--text-secondary);
  text-align: center;
}

/* Example Box */
.example-container {
  background: rgba(255,255,255,0.01);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.25rem;
}

.example-container h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-main);
}

.example-list {
  padding-left: 1.2rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.example-list strong {
  color: #fff;
}

/* --- Settings pane styles --- */
.settings-container {
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.settings-container h2 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.settings-intro {
  color: var(--text-secondary);
  margin-top: -1.25rem;
  font-size: 0.95rem;
}

.settings-section {
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.settings-section h3 {
  font-size: 1.1rem;
  font-weight: 600;
}

/* Preset buttons */
.preset-ranges {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.preset-btn {
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1rem 0.5rem;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  transition: all var(--transition-speed) ease;
}

.preset-btn:hover {
  background: rgba(255,255,255,0.05);
  border-color: var(--border-hover);
}

.preset-btn.active {
  background: rgba(99, 102, 241, 0.08);
  border-color: var(--primary);
}

.preset-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-main);
}

.preset-years {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.custom-range-inputs {
  display: flex;
  gap: 1rem;
  animation: fadeIn 0.2s ease-out;
}

.input-group {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.input-group label {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.input-group input {
  background: rgba(0, 0, 0, 0.25);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.6rem 0.85rem;
  color: #fff;
  font-family: inherit;
  font-size: 0.95rem;
  outline: none;
  transition: all var(--transition-speed) ease;
}

.input-group input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-glow);
}

/* Switches */
.setting-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 2rem;
}

.setting-info {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  max-width: 80%;
}

.setting-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-main);
}

.setting-desc {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
  flex-shrink: 0;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(255,255,255,0.08);
  transition: .3s;
  border-radius: 24px;
  border: 1px solid var(--border-color);
}

.slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 3px;
  bottom: 3px;
  background-color: var(--text-secondary);
  transition: .3s;
  border-radius: 50%;
}

input:checked + .slider {
  background-color: var(--primary-glow);
  border-color: var(--primary);
}

input:checked + .slider:before {
  transform: translateX(20px);
  background-color: var(--primary);
}

/* Danger Zone */
.danger-zone {
  border-top: 1px solid rgba(239, 68, 68, 0.2);
}

.danger-btn {
  background: rgba(239, 68, 68, 0.1);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: #f87171;
  padding: 0.6rem 1.25rem;
  border-radius: 10px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  transition: all var(--transition-speed) ease;
}

.danger-btn:hover {
  background: var(--error);
  color: white;
  border-color: var(--error);
  box-shadow: 0 4px 15px rgba(239, 68, 68, 0.3);
}

/* --- Footer --- */
.app-footer {
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-top: 1rem;
}

.app-footer p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.hotkey-legend {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.hotkey-legend kbd {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 3px;
  padding: 0.05rem 0.25rem;
  font-size: 0.7rem;
  color: var(--text-secondary);
}

/* --- Mobile Responsiveness --- */
@media (max-width: 680px) {
  .app-container {
    padding: 1rem;
  }
  
  .app-header {
    flex-direction: column;
    align-items: stretch;
    gap: 1rem;
  }
  
  .logo-area {
    justify-content: center;
  }
  
  .stats-widget {
    justify-content: space-around;
  }
  
  .stat-item {
    flex: 1;
    min-width: unset;
  }
  
  .answers-grid {
    grid-template-columns: repeat(4, 1fr);
  }
  
  .day-btn[data-day="0"] {
    grid-column: span 2;
  }
  
  .preset-ranges {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .learn-grid {
    grid-template-columns: 1fr;
  }
  
  .learn-card.full-width {
    grid-column: span 1;
  }
  
  .anchors-grid-visual {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 440px) {
  .answers-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  
  .day-btn[data-day="0"] {
    grid-column: span 2;
  }
  
  .setting-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
  
  .setting-info {
    max-width: 100%;
  }
  
  .preset-ranges {
    grid-template-columns: 1fr;
  }
}