/* ============================================================
   Telegram theme CSS variables with browser fallbacks
   ============================================================ */
:root {
  --tg-theme-bg-color: #ffffff;
  --tg-theme-text-color: #000000;
  --tg-theme-hint-color: #999999;
  --tg-theme-link-color: #2481cc;
  --tg-theme-button-color: #2481cc;
  --tg-theme-button-text-color: #ffffff;
  --tg-theme-secondary-bg-color: #f5f5f5;
}

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

html, body {
  height: 100%;
  width: 100%;
  overflow: hidden;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
               Helvetica, Arial, sans-serif;
  background-color: var(--tg-theme-bg-color);
  color: var(--tg-theme-text-color);
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

/* ============================================================
   Screens
   ============================================================ */
.screen {
  display: none;
  flex-direction: column;
  align-items: center;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  overflow-y: auto;
  overflow-x: hidden;
}

.screen-active {
  display: flex;
}

/* ============================================================
   Loading screen
   ============================================================ */
#screen-loading {
  justify-content: center;
}

.loading-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.loading-text {
  color: var(--tg-theme-hint-color);
  font-size: 1rem;
}

/* Spinner */
.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--tg-theme-secondary-bg-color);
  border-top-color: var(--tg-theme-button-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Error state */
.error-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 24px;
  text-align: center;
}

.error-icon {
  font-size: 3rem;
  line-height: 1;
}

.error-message {
  font-size: 1rem;
  color: var(--tg-theme-text-color);
  max-width: 320px;
}

/* Warning banner for browser mode */
.browser-warning {
  background: #fff3cd;
  color: #856404;
  padding: 8px 14px;
  font-size: 0.8rem;
  text-align: center;
  width: 100%;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 100;
}

/* ============================================================
   Exercise screen
   ============================================================ */
#screen-exercise {
  padding: 0;
  gap: 0;
  overflow: hidden;
}

/* ── Header ── */
#exercise-header {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px 4px;
  flex-shrink: 0;
}

.header-stat {
  font-size: 0.82rem;
  color: var(--tg-theme-hint-color);
  font-variant-numeric: tabular-nums;
}

/* ── Progress bar ── */
#progress-bar-wrap {
  width: 100%;
  height: 3px;
  background: var(--tg-theme-secondary-bg-color);
  flex-shrink: 0;
}

#progress-bar {
  height: 100%;
  background: var(--tg-theme-button-color);
  width: 0%;
  transition: width 0.4s ease;
}

/* ── Selected indicator ── */
.selected-indicator {
  width: 100%;
  padding: 6px 16px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--tg-theme-button-color);
  background: transparent;
  flex-shrink: 0;
  min-height: 28px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.selected-indicator.hidden {
  visibility: hidden;
}

/* ============================================================
   Matching grid
   ============================================================ */
.matching-grid {
  display: flex;
  gap: 8px;
  padding: 0 10px 10px;
  width: 100%;
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  align-items: flex-start;
}

.match-col {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}

/* ── Tile ── */
.match-tile {
  width: 100%;
  min-height: 52px;
  padding: 10px 12px;
  background: var(--tg-theme-secondary-bg-color);
  border-radius: 12px;
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--tg-theme-text-color);
  text-align: center;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1.3;
  word-break: break-word;
  border: 2px solid transparent;
  transition: background 0.15s, border-color 0.15s, opacity 0.3s, transform 0.1s;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.match-tile:active {
  transform: scale(0.97);
}

/* Selected (left column tap) */
.match-tile.selected {
  border-color: var(--tg-theme-button-color);
  background: var(--tg-theme-secondary-bg-color); /* fallback for Chrome <111 / older Telegram WebView */
  background: color-mix(in srgb, var(--tg-theme-button-color) 12%, var(--tg-theme-secondary-bg-color));
}

/* Correct match flash */
.match-tile.correct {
  background: #27ae60;
  color: #ffffff;
  border-color: #27ae60;
}

/* Wrong match flash */
.match-tile.wrong {
  background: #ff4444;
  color: #ffffff;
  border-color: #ff4444;
  animation: shake 0.4s ease;
}

/* Matched (dimmed) */
.match-tile.matched {
  opacity: 0.35;
  cursor: default;
  pointer-events: none;
}

/* Shake animation for wrong matches */
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%       { transform: translateX(-5px); }
  40%       { transform: translateX(5px); }
  60%       { transform: translateX(-4px); }
  80%       { transform: translateX(4px); }
}

/* ============================================================
   Results screen
   ============================================================ */
#screen-results {
  justify-content: center;
  padding: 24px 20px 80px;
}

.results-content {
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.results-title {
  font-size: 1.8rem;
  font-weight: 700;
  text-align: center;
  color: var(--tg-theme-text-color);
}

.results-time {
  font-size: 1rem;
  color: var(--tg-theme-hint-color);
  text-align: center;
}

.results-breakdown {
  width: 100%;
  background: var(--tg-theme-secondary-bg-color);
  border-radius: 14px;
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.results-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 1rem;
}

.results-row-label {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--tg-theme-text-color);
}

.results-row-count {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--tg-theme-text-color);
}

/* ============================================================
   Utility
   ============================================================ */
.hidden {
  display: none !important;
}