/* ============================================================
   GAME.CSS — Solo gameplay, challenge and result screens
   ============================================================ */

/* ---- HUD / top bar ---- */
.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-3);
}
.top-bar .stat-pill { font-variant-numeric: tabular-nums; }

/* ---- Timer ---- */
.timer-wrap {
  height: 12px;
  background: var(--surface-2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-pill);
  overflow: hidden;
  margin-bottom: var(--space-3);
}
.timer-bar {
  height: 100%;
  width: 100%;
  border-radius: var(--radius-pill);
  background: linear-gradient(90deg, var(--primary), var(--info));
  transition: width 1s linear, background var(--dur-base) var(--ease-out);
}
.timer-bar.warn   { background: linear-gradient(90deg, var(--warn), var(--accent-yellow)); }
.timer-bar.danger { background: linear-gradient(90deg, var(--error), var(--warn)); animation: pulse-bar 0.6s infinite; }

/* ---- Marathon track (calmer) ---- */
.marathon-track {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--space-3) var(--space-4);
  margin-bottom: var(--space-3);
  overflow: hidden;
}
.track-label {
  font-size: 0.6875rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: var(--space-2);
}
.track-inner { display: flex; align-items: center; height: 2.75rem; width: 100%; position: relative; }
.track-dots { display: flex; gap: 0; width: 100%; justify-content: space-between; align-items: center; position: relative; }
.track-dot {
  width: 1.75rem;
  height: 1.75rem;
  border-radius: 50%;
  border: 2px solid var(--border-strong);
  background: var(--surface-2);
  color: var(--text-faint);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.6875rem;
  font-weight: 700;
  flex-shrink: 0;
  transition: all var(--dur-fast) var(--ease-out);
}
.track-dot.done     { background: var(--success); border-color: var(--success); color: var(--text-on-accent); }
.track-dot.current  { background: var(--primary); border-color: var(--primary); color: var(--text-on-accent); box-shadow: 0 0 0 4px color-mix(in srgb, var(--primary) 25%, transparent); animation: current-pulse 1.2s ease-in-out infinite; }
.track-dot.challenge{ background: var(--accent-violet); border-color: var(--accent-violet); color: var(--text-on-accent); }
.track-dot.boss     { background: var(--error); border-color: var(--error); color: var(--text-on-accent); }
.runner {
  position: absolute;
  font-size: 1.5rem;
  top: 50%;
  transform: translateY(-50%) scaleX(-1);
  transition: left var(--dur-slow) var(--ease-bounce);
  z-index: 2;
  animation: runner-bounce 0.4s ease-in-out infinite alternate;
}

/* ---- Equation card ---- */
.eq-card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem 1.375rem;
  text-align: center;
  margin-bottom: var(--space-3);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: border-color var(--dur-base) var(--ease-out), box-shadow var(--dur-base) var(--ease-out);
}
.eq-card.correct { border-color: var(--success); box-shadow: 0 0 0 3px color-mix(in srgb, var(--success) 25%, transparent); }
.eq-card.wrong   { border-color: var(--error);   box-shadow: 0 0 0 3px color-mix(in srgb, var(--error) 25%, transparent); animation: shake 0.4s; }

.equation {
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 1.4rem + 3vw, 5rem);
  font-weight: 700;
  letter-spacing: 0.02em;
  margin-bottom: 0.5rem;
  line-height: 1.3;
  white-space: pre-line;
  color: var(--text);
}
.eq-hint { font-size: 0.8125rem; font-weight: 600; color: var(--text-muted); }
.multiplier {
  display: none;
  margin-top: 0.625rem;
  background: linear-gradient(135deg, var(--accent-orange), var(--accent-yellow));
  color: #1a1200;
  border-radius: var(--radius-pill);
  padding: 0.25rem 0.875rem;
  font-size: 0.8125rem;
  font-weight: 900;
}
.multiplier.show { display: inline-block; }

/* ---- Multi-line equation layouts ---- */
.sys-wrap { display: inline-flex; align-items: stretch; gap: 0.5rem; }
.sys-brace { font-size: clamp(2.5rem, 10vw, 4.375rem); line-height: 1; color: var(--text-muted); font-weight: 100; align-self: center; }
.sys-lines { display: flex; flex-direction: column; justify-content: center; gap: 0.25rem; text-align: left; }
.sys-line { font-family: var(--font-display); font-size: clamp(1.25rem, 5vw, 2.25rem); font-weight: 700; letter-spacing: 0.02em; line-height: 1.2; white-space: nowrap; }
.deriv-func { font-family: var(--font-display); font-size: clamp(1.5rem, 6vw, 2.75rem); font-weight: 700; letter-spacing: 0.02em; line-height: 1.2; }
.deriv-question { font-family: var(--font-display); font-size: clamp(1.25rem, 5vw, 2.125rem); font-weight: 700; letter-spacing: 0.02em; color: var(--primary); margin-top: 0.25rem; }

/* ---- Answer input ---- */
.input-wrap { display: flex; gap: var(--space-3); margin-bottom: var(--space-3); }

/* ---- "How to solve" button ---- */
.explain-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  width: 100%;
  min-height: 48px;
  margin: 0 0 var(--space-3);
  background: color-mix(in srgb, var(--primary) 10%, transparent);
  border: 1.5px dashed color-mix(in srgb, var(--primary) 45%, transparent);
  border-radius: var(--radius-md);
  color: var(--primary);
  font-family: var(--font-body);
  font-weight: 800;
  font-size: 0.9375rem;
  cursor: pointer;
  transition: background-color var(--dur-fast) var(--ease-out), border-color var(--dur-fast) var(--ease-out);
}
.explain-btn:hover { background: color-mix(in srgb, var(--primary) 18%, transparent); border-color: var(--primary); }
.explain-btn:disabled { opacity: 0.4; pointer-events: none; }

.progress-text {
  text-align: center;
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--text-muted);
  margin-top: auto;
  padding-top: 0.5rem;
}

/* ============================================================
   CHALLENGE INTERSTITIAL
   ============================================================ */
.challenge-card {
  background: var(--surface);
  border: 2px solid color-mix(in srgb, var(--accent-violet) 60%, transparent);
  border-radius: var(--radius-lg);
  padding: 2.5rem 1.875rem;
  max-width: min(31.25rem, 88vw);
  width: 100%;
  box-shadow: var(--shadow-xl);
  animation: card-appear var(--dur-slow) var(--ease-bounce);
}
.challenge-big-icon  { font-size: 4.5rem; margin-bottom: 0.875rem; display: block; animation: bounce 1.2s ease-in-out infinite; }
.challenge-big-title { font-family: var(--font-display); font-size: 2.5rem; font-weight: 800; letter-spacing: 0.02em; color: var(--accent-violet); margin-bottom: 0.5rem; }
.challenge-big-desc  { font-size: 1.0625rem; font-weight: 600; margin-bottom: 1.25rem; line-height: 1.5; color: var(--text); }
.challenge-reward {
  background: color-mix(in srgb, var(--warn) 12%, transparent);
  border: 2px solid color-mix(in srgb, var(--warn) 40%, transparent);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  margin-bottom: 1.375rem;
  font-weight: 700;
  color: var(--warn);
  font-size: 0.875rem;
}

/* ============================================================
   SOLO RESULT
   ============================================================ */
.result-card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 2.5rem 1.75rem;
  max-width: min(31.25rem, 88vw);
  width: 100%;
  box-shadow: var(--shadow-xl);
  animation: card-appear var(--dur-slow) var(--ease-bounce);
}
.result-emoji    { font-size: 4.5rem; margin-bottom: 0.875rem; display: block; }
.result-title    { font-family: var(--font-display); font-size: 3rem; font-weight: 800; letter-spacing: 0.02em; margin-bottom: 0.375rem; color: var(--text); }
.result-subtitle { font-size: 0.9375rem; font-weight: 600; color: var(--text-muted); margin-bottom: 0.5rem; }
.result-message  { font-size: 0.875rem; font-weight: 700; color: var(--info); margin-bottom: 0.5rem; min-height: 1.2em; }
.result-best     { font-size: 0.8125rem; font-weight: 700; color: var(--text-muted); margin-bottom: 1rem; min-height: 1.1em; }
.stars-wrap      { font-size: 1.75rem; margin-bottom: var(--space-3); }

.result-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-3); margin-bottom: var(--space-5); }
.result-stat  { background: var(--surface-2); border: 1.5px solid var(--border); border-radius: var(--radius-md); padding: 0.875rem 0.625rem; }
.result-stat-val   { font-family: var(--font-display); font-size: 1.875rem; font-weight: 800; letter-spacing: 0.02em; }
.result-stat-label { font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.04em; text-transform: uppercase; color: var(--text-muted); margin-top: 0.25rem; }

.ranking-name-wrap {
  margin-bottom: var(--space-5);
  padding: var(--space-4);
  background: color-mix(in srgb, var(--primary) 8%, transparent);
  border: 1.5px solid color-mix(in srgb, var(--primary) 24%, transparent);
  border-radius: var(--radius-md);
}
.ranking-name-label { display: block; font-size: 0.75rem; font-weight: 800; letter-spacing: 0.03em; color: var(--primary); margin-bottom: 0.625rem; text-transform: uppercase; }
.ranking-name-row { display: flex; gap: 0.5rem; }
.ranking-save-btn {
  padding: 0.625rem 1.125rem;
  background: var(--primary);
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-on-accent);
  font-weight: 800;
  font-size: 0.8125rem;
  white-space: nowrap;
}
.ranking-save-btn:hover { background: var(--primary-hover); }
.ranking-save-btn:disabled { opacity: 0.6; cursor: default; }
.ranking-saved-msg { font-size: 0.75rem; font-weight: 700; color: var(--success); margin-top: 0.5rem; animation: fade-in var(--dur-base) var(--ease-out); }

@media (max-width: 480px) {
  .result-stats { grid-template-columns: 1fr; }
}