/* ═══════════════════════════════════════════════════════
   SRP Study — style.css
   Design system: IBM Plex Mono + Sora, dark-mode, clean
   ═══════════════════════════════════════════════════════ */

/* ── 1. Tokens ─────────────────────────────────────────── */
:root {
  /* Colors */
  --color-bg:         #0a0c10;
  --color-surface:    #0f1218;
  --color-surface-2:  #141920;
  --color-border:     #1e2630;
  --color-border-2:   #2a3340;
  --color-text:       #e8edf5;
  --color-muted:      #7a8a9e;
  --color-hint:       #4a5668;

  --color-accent:     #3d8bff;
  --color-accent-dim: #1a3d70;
  --color-green:      #12c26b;
  --color-green-dim:  #0a3320;
  --color-red:        #e84040;
  --color-red-dim:    #3d1010;
  --color-yellow:     #f0b429;
  --color-yellow-dim: #3d2c08;

  --color-pill-bg:    #141c28;
  --color-pill-border:#1e2e44;

  /* Typography */
  --font-body:   'Sora', sans-serif;
  --font-mono:   'IBM Plex Mono', monospace;

  /* Sizing */
  --radius-sm:   8px;
  --radius-md:   14px;
  --radius-lg:   20px;
  --radius-pill: 999px;

  --space-xs:  4px;
  --space-sm:  8px;
  --space-md:  16px;
  --space-lg:  24px;
  --space-xl:  40px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --dur-fast: 150ms;
  --dur-med:  280ms;
}

/* ── 2. Reset & Base ───────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100dvh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── 3. Top Bar ────────────────────────────────────────── */
.topbar {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 12, 16, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.topbar__inner {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-sm) var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.topbar__logo {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  color: var(--color-accent);
  text-transform: uppercase;
}

.topbar__nav {
  display: flex;
  gap: var(--space-sm);
}

/* ── 4. Progress Bar ───────────────────────────────────── */
.progress-bar {
  height: 3px;
  background: var(--color-border);
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  background: var(--color-accent);
  width: 0%;
  transition: width 500ms var(--ease-out);
  border-radius: var(--radius-pill);
}

/* ── 5. Main Layout ────────────────────────────────────── */
.main {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-lg) var(--space-md);
  min-height: calc(100dvh - 53px);
}

/* ── 6. View transitions ───────────────────────────────── */
.view {
  animation: viewIn var(--dur-med) var(--ease-out) both;
}

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

/* ── 7. Card ───────────────────────────────────────────── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.card--warning {
  border-color: var(--color-yellow-dim);
  background: linear-gradient(135deg, var(--color-surface) 0%, #1a1500 100%);
}

.card--success {
  border-color: var(--color-green-dim);
  background: linear-gradient(135deg, var(--color-surface) 0%, #001a0d 100%);
}

.card__header {
  padding: var(--space-xl) var(--space-xl) var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.card__title {
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.02em;
  color: var(--color-text);
}

.card__subtitle {
  margin-top: var(--space-sm);
  color: var(--color-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

.card__body {
  padding: var(--space-lg) var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.card__footer {
  padding: var(--space-lg) var(--space-xl) var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.card__footer--row {
  flex-direction: row;
  flex-wrap: wrap;
  align-items: center;
}

/* ── 8. Buttons ────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 12px 22px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  transition: background var(--dur-fast), border-color var(--dur-fast),
              transform var(--dur-fast), opacity var(--dur-fast);
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.38;
  cursor: not-allowed;
  pointer-events: none;
}

.btn--primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}
.btn--primary:hover:not(:disabled) { background: #5a9fff; border-color: #5a9fff; }
.btn--primary:active:not(:disabled) { transform: scale(0.97); }

.btn--ghost {
  background: transparent;
  border-color: var(--color-border-2);
  color: var(--color-muted);
}
.btn--ghost:hover:not(:disabled) { border-color: var(--color-accent); color: var(--color-text); }

.btn--danger {
  background: var(--color-red-dim);
  border-color: var(--color-red);
  color: var(--color-red);
}
.btn--danger:hover:not(:disabled) { background: var(--color-red); color: #fff; }

.btn--success {
  background: var(--color-green-dim);
  border-color: var(--color-green);
  color: var(--color-green);
}
.btn--success.active {
  background: var(--color-green);
  color: #fff;
}

.btn--error {
  background: var(--color-red-dim);
  border-color: var(--color-red);
  color: var(--color-red);
}
.btn--error.active {
  background: var(--color-red);
  color: #fff;
}

.btn--sm {
  font-size: 0.82rem;
  padding: 7px 14px;
  border-radius: var(--radius-sm);
}

.btn--full { width: 100%; }

/* Button pop animation */
@keyframes btn-pop {
  0%   { transform: scale(1); }
  40%  { transform: scale(0.95); }
  100% { transform: scale(1); }
}
.btn.popping { animation: btn-pop 350ms var(--ease-out); }

/* Button shake on wrong */
@keyframes btn-shake {
  0%, 100% { transform: translateX(0); }
  15%       { transform: translateX(-7px); }
  30%       { transform: translateX(7px); }
  50%       { transform: translateX(-5px); }
  70%       { transform: translateX(5px); }
  90%       { transform: translateX(-2px); }
}
.btn.shaking { animation: btn-shake 420ms ease-in-out; }

/* ── 9. Number grid (meta-comprehension) ───────────────── */
.btn-grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-sm);
}

.btn-grid .btn {
  flex: 0 0 auto;
  min-width: 48px;
  padding: 10px 14px;
  font-family: var(--font-mono);
}

.btn-grid .btn.selected {
  background: var(--color-accent-dim);
  border-color: var(--color-accent);
  color: var(--color-accent);
}

/* ── 10. Form fields ───────────────────────────────────── */
.field {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.field__label {
  font-size: 0.82rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.field__input {
  width: 100%;
  padding: 12px 16px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-2);
  border-radius: var(--radius-md);
  color: var(--color-text);
  font-family: var(--font-body);
  font-size: 1rem;
  transition: border-color var(--dur-fast), box-shadow var(--dur-fast);
  -webkit-appearance: none;
  appearance: none;
}

.field__input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(61, 139, 255, 0.15);
}

.field__input--select {
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%237a8a9e' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 40px;
}

.field__hint {
  font-size: 0.82rem;
  color: var(--color-hint);
  line-height: 1.5;
}

/* ── 11. Trial View ────────────────────────────────────── */
.trial-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.trial-img-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  background: #fff;
  border-radius: var(--radius-md);
  overflow: hidden;
  min-height: 240px;
  max-height: 340px;
}

.trial-img {
  max-width: 100%;
  max-height: 340px;
  object-fit: contain;
  display: block;
}

.trial-fill-prompt {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 500;
  text-align: center;
  color: var(--color-text);
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-2);
  border-radius: var(--radius-md);
  padding: var(--space-md) var(--space-lg);
  letter-spacing: 0.04em;
}

.trial-label {
  display: block;
  margin-bottom: 0;
}

.trial-input-row {
  display: flex;
  gap: var(--space-sm);
}

.trial-input {
  flex: 1;
}

.trial-submit {
  flex-shrink: 0;
  min-width: 110px;
}

/* ── 12. Feedback ──────────────────────────────────────── */
.feedback-block {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-2);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  animation: viewIn var(--dur-med) var(--ease-out) both;
}

.feedback-block--correct { border-color: var(--color-green-dim); }
.feedback-block--incorrect { border-color: var(--color-red-dim); }

.feedback-pills {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.pill {
  padding: 5px 12px;
  background: var(--color-pill-bg);
  border: 1px solid var(--color-pill-border);
  border-radius: var(--radius-pill);
  font-size: 0.88rem;
  color: var(--color-muted);
  white-space: nowrap;
}

.pill strong {
  color: var(--color-text);
  font-family: var(--font-mono);
}

.pill--correct { border-color: var(--color-green-dim); }
.pill--correct strong { color: var(--color-green); }

.pill--wrong { border-color: var(--color-red-dim); }
.pill--wrong strong { color: var(--color-red); }

/* ── 13. Countdown ─────────────────────────────────────── */
.countdown {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--color-hint);
  text-align: right;
  min-height: 1.4em;
}

/* ── 14. Warnings ──────────────────────────────────────── */
.warn {
  font-size: 0.88rem;
  color: var(--color-yellow);
  padding: var(--space-sm) var(--space-md);
  background: var(--color-yellow-dim);
  border: 1px solid rgba(240, 180, 41, 0.2);
  border-radius: var(--radius-sm);
}

/* ── 15. Hints ─────────────────────────────────────────── */
.hint-enter {
  font-size: 0.82rem;
  color: var(--color-hint);
  text-align: center;
}

.hint-enter kbd {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 2px 6px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-2);
  border-radius: 4px;
  color: var(--color-muted);
}

.hint-sm {
  font-size: 0.82rem;
  color: var(--color-muted);
  line-height: 1.5;
}

/* ── 16. Meta-comprehension block ──────────────────────── */
.meta-block {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.meta-block__prompt {
  font-size: 0.95rem;
  color: var(--color-muted);
}

.meta-block__input {
  max-width: 180px;
}

/* ── 17. Instructions toggle ───────────────────────────── */
.instr-toggle {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.pdf-frame {
  width: 100%;
  height: 68vh;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: #fff;
}

.pdf-frame--inline {
  height: 56vh;
}

.collapse {
  overflow: hidden;
  max-height: 0;
  transition: max-height 300ms var(--ease-out);
}

.collapse.open {
  max-height: 70vh;
}

/* ── 18. Summary stats ─────────────────────────────────── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--space-md);
}

.stat-card {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.stat-card__value {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 500;
  color: var(--color-accent);
  line-height: 1;
}

.stat-card__label {
  font-size: 0.78rem;
  color: var(--color-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ── 19. Toast ─────────────────────────────────────────── */
.toast {
  position: fixed;
  bottom: var(--space-lg);
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-2);
  border-radius: var(--radius-md);
  padding: 12px 20px;
  font-size: 0.9rem;
  color: var(--color-text);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
  white-space: nowrap;
  animation: toastIn 250ms var(--ease-out);
  pointer-events: none;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateX(-50%) translateY(8px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ── 20. Confetti canvas (full-screen) ─────────────────── */
#confettiCanvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 9999;
}

/* ── 21. Mobile ────────────────────────────────────────── */
@media (max-width: 600px) {
  .card__header,
  .card__body,
  .card__footer {
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
  }

  .card__header { padding-top: var(--space-lg); }
  .card__footer { padding-bottom: var(--space-lg); }

  .card__title { font-size: 1.3rem; }

  .trial-img-wrap {
    min-height: 180px;
    max-height: 260px;
  }

  .trial-input-row {
    flex-direction: column;
  }

  .trial-submit { width: 100%; }

  .pdf-frame { height: 55vh; }
  .pdf-frame--inline { height: 45vh; }

  .card__footer--row {
    flex-direction: column;
    align-items: stretch;
  }

  .stats-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 380px) {
  .card__header,
  .card__body,
  .card__footer {
    padding-left: var(--space-md);
    padding-right: var(--space-md);
  }
}