:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-2: #eef1f7;
  --border: #dbe0ea;
  --text: #0b1220;
  --text-muted: #5b6475;
  --accent: #3558d4;
  --accent-fg: #ffffff;
  --correct: #198754;
  --correct-bg: #d8f0e0;
  --wrong: #c1343b;
  --wrong-bg: #f7dcde;
  --shadow: 0 1px 3px rgba(11, 18, 32, 0.06), 0 4px 12px rgba(11, 18, 32, 0.04);
  --radius: 14px;
  --pad: 16px;
  --tap: 48px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --surface: #141c2e;
    --surface-2: #1b243a;
    --border: #27314a;
    --text: #e6eaf3;
    --text-muted: #9aa5bd;
    --accent: #6d8bff;
    --accent-fg: #0b1220;
    --correct: #6ee39a;
    --correct-bg: #163a27;
    --wrong: #ff8a90;
    --wrong-bg: #3a1a1d;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 4px 16px rgba(0, 0, 0, 0.35);
  }
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji";
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -webkit-tap-highlight-color: transparent;
}

body {
  min-height: 100dvh;
  padding: env(safe-area-inset-top) env(safe-area-inset-right)
    env(safe-area-inset-bottom) env(safe-area-inset-left);
}

#app {
  max-width: 720px;
  margin: 0 auto;
  padding: 16px 14px 24px;
}

.screen {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.hidden {
  display: none !important;
}

h1 {
  margin: 0;
  font-size: 1.6rem;
  letter-spacing: -0.01em;
}

h2 {
  margin: 0 0 8px;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  font-weight: 600;
}

p {
  margin: 0 0 8px;
}

.sub {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin: 4px 0 0;
}

.tiny {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: 0;
}

.home-header {
  padding: 12px 4px 4px;
}

.signin-card,
.pending-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.signin-card form {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 4px 0 0;
}
.signin-label {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-weight: 600;
  letter-spacing: 0.02em;
}
.signin-card input[type="email"] {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  min-height: var(--tap);
  padding: 12px 14px;
  font-size: 16px; /* prevent iOS zoom on focus */
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  outline: none;
}
.signin-card input[type="email"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(53, 88, 212, 0.18);
}

#home-user {
  margin-top: 6px;
}

.admin-user-list {
  list-style: none;
  padding: 0;
  margin: 8px 0 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.admin-user-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  background: var(--card-alt, rgba(255, 255, 255, 0.03));
  border: 1px solid var(--border, rgba(255, 255, 255, 0.08));
  border-radius: 10px;
}
.admin-user-main {
  flex: 1;
  min-width: 0;
}
.admin-user-name {
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.admin-user-email {
  font-size: 12px;
  opacity: 0.7;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.admin-user-role {
  font-size: 11px;
  opacity: 0.7;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.admin-approve-btn {
  padding: 8px 14px;
  background: var(--accent, #3558d4);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}
.admin-approve-btn:disabled {
  opacity: 0.5;
  cursor: default;
}
.admin-deny-btn {
  padding: 8px 14px;
  background: transparent;
  color: var(--wrong);
  border: 1px solid var(--wrong);
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}
.admin-deny-btn:disabled {
  opacity: 0.5;
  cursor: default;
}
.admin-delete-btn {
  padding: 8px 14px;
  background: transparent;
  color: var(--muted, #666);
  border: 1px solid var(--muted, #666);
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}
.admin-delete-btn:disabled {
  opacity: 0.5;
  cursor: default;
}
.admin-block-btn {
  padding: 8px 14px;
  background: var(--wrong);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}
.admin-block-btn:disabled {
  opacity: 0.5;
  cursor: default;
}
.admin-user-actions {
  display: flex;
  gap: 8px;
  flex-shrink: 0;
}
.admin-user-role.role-admin {
  color: var(--accent);
  opacity: 1;
  font-weight: 700;
}
.admin-tabs {
  display: flex;
  gap: 4px;
  background: var(--surface-2);
  padding: 4px;
  border-radius: 10px;
  margin-bottom: 12px;
}
.admin-tab {
  flex: 1;
  min-height: 40px;
  padding: 8px 10px;
  background: transparent;
  color: var(--text-muted);
  border: none;
  border-radius: 7px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
}
.admin-tab.active {
  background: var(--surface);
  color: var(--text);
  box-shadow: 0 1px 2px rgba(11, 18, 32, 0.08);
}
.admin-tab-panel {
  margin-top: 4px;
}

/* Packs screen — pack row descriptions and the active toggle. Reuses
   .admin-user-row / .admin-user-main / .admin-user-actions for layout. */
.pack-description {
  white-space: normal;
  line-height: 1.35;
  font-size: 0.85rem;
  opacity: 0.7;
  margin-top: 2px;
}
.pack-meta {
  font-size: 11px;
  opacity: 0.6;
  margin-top: 2px;
  text-transform: none;
  letter-spacing: 0;
}
.pack-active-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  color: var(--text-muted);
}
.pack-active-label input[type="checkbox"] {
  accent-color: var(--accent);
  width: 18px;
  height: 18px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: var(--pad);
  box-shadow: var(--shadow);
}

.settings h2:not(:first-of-type) {
  margin-top: 20px;
}

.radio-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 10px;
  border-radius: 10px;
  min-height: var(--tap);
  cursor: pointer;
  user-select: none;
}

.radio-group label:has(input:checked) {
  background: var(--surface-2);
  outline: 1.5px solid var(--accent);
  outline-offset: -1.5px;
}

.radio-group input[type="radio"] {
  accent-color: var(--accent);
  width: 18px;
  height: 18px;
  flex: none;
}

button {
  font: inherit;
  color: inherit;
  cursor: pointer;
}

button.primary {
  display: block;
  width: 100%;
  margin-top: 20px;
  padding: 14px 18px;
  min-height: var(--tap);
  background: var(--accent);
  color: var(--accent-fg);
  border: none;
  border-radius: 12px;
  font-size: 1.05rem;
  font-weight: 600;
}

button.primary:active {
  transform: translateY(1px);
}

button.primary:disabled {
  background: var(--surface-2);
  color: var(--text-muted);
  cursor: not-allowed;
}

button.link {
  background: none;
  border: none;
  color: var(--accent);
  padding: 10px 0;
  font-size: 0.95rem;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.home-footer {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 8px 0 24px;
}

/* ------- Card screen ------- */

.card-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 4px 2px;
}

.icon-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  width: 44px;
  height: 44px;
  font-size: 1.25rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.progress-pill {
  background: var(--surface-2);
  padding: 8px 14px;
  border-radius: 999px;
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  font-size: 0.95rem;
}

.card-id {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.card-body {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card-body .question-stem {
  font-size: 1.05rem;
}

/* ---- Short-answer question stem (structured parts) ---- */

.text-stem {
  display: flex;
  flex-direction: column;
  gap: 12px;
  font-size: 1rem;
}

.stem-preamble {
  font-size: 1.02rem;
  color: var(--text);
}

.stem-part {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  background: var(--surface-2);
  border-radius: 10px;
  line-height: 1.45;
}

.stem-part.level-2 {
  margin-left: 18px;
  background: transparent;
  border-left: 2px solid var(--border);
  border-radius: 0;
  padding: 6px 12px;
}

.stem-part .part-label {
  flex: none;
  font-weight: 600;
  color: var(--accent);
  min-width: 22px;
  font-variant-numeric: tabular-nums;
}

.stem-part .part-text {
  flex: 1 1 auto;
  min-width: 0;
  font-weight: 400;
}

.stem-part .part-text p {
  margin: 0;
}

.stem-part .mark-pill {
  flex: none;
  margin-left: auto;
  align-self: flex-start;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.72rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 999px;
  white-space: nowrap;
  letter-spacing: 0.02em;
}

.stem-part.level-2 .mark-pill {
  background: var(--surface-2);
}

/* ---- SBA options ---- */

.options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.options-list li {
  display: block;
}

.option-btn {
  display: flex;
  align-items: baseline;
  gap: 12px;
  width: 100%;
  text-align: left;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  min-height: var(--tap);
  font-size: 1rem;
  line-height: 1.45;
  color: var(--text);
  transition: border-color 0.1s, background 0.1s;
}

.option-btn .opt-letter {
  flex: none;
  font-weight: 700;
  color: var(--accent);
  min-width: 22px;
  font-variant-numeric: tabular-nums;
}

.option-btn .opt-text {
  flex: 1 1 auto;
  min-width: 0;
}

.option-btn.selected {
  border-color: var(--accent);
  background: var(--surface-2);
}

.option-btn.correct {
  border-color: var(--correct);
  background: var(--correct-bg);
}

.option-btn.correct .opt-letter {
  color: var(--correct);
}

.option-btn.wrong {
  border-color: var(--wrong);
  background: var(--wrong-bg);
}

.option-btn.wrong .opt-letter {
  color: var(--wrong);
}

.option-btn .mark {
  flex: none;
  margin-left: auto;
  align-self: center;
  font-weight: 700;
  font-size: 1.1rem;
}

.option-btn.correct .mark {
  color: var(--correct);
}

.option-btn.wrong .mark {
  color: var(--wrong);
}

.option-btn[disabled] {
  cursor: default;
}

.reveal-bar {
  display: flex;
  gap: 10px;
}

.reveal-bar button {
  flex: 1;
  padding: 14px;
  min-height: var(--tap);
  border-radius: 12px;
  border: 1.5px solid var(--accent);
  background: var(--accent);
  color: var(--accent-fg);
  font-weight: 600;
  font-size: 1rem;
}

.reveal-bar button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.md-block {
  border-top: 1px solid var(--border);
  padding-top: 14px;
}

.md-block:first-child {
  border-top: none;
  padding-top: 0;
}

.md-block h3 {
  margin: 0 0 8px;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  font-weight: 600;
}

.md-content {
  font-size: 0.98rem;
}

.md-content p {
  margin: 0 0 10px;
}

.md-content ul,
.md-content ol {
  padding-left: 20px;
  margin: 0 0 10px;
}

.md-content li {
  margin-bottom: 4px;
}

.md-content strong {
  color: var(--text);
}

.md-content code {
  background: var(--surface-2);
  padding: 1px 5px;
  border-radius: 4px;
  font-size: 0.92em;
}

.md-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 8px 0;
  display: block;
}

/* Markdown editor with preview */
.md-editor-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.md-preview {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 12px;
  min-height: 36px;
  background: var(--surface-2);
  font-size: 0.93em;
  display: none;
}
.md-preview.has-content {
  display: block;
}
.md-preview img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 6px 0;
  display: block;
}
.md-upload-btn {
  align-self: flex-start;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 3px 10px;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 0.82em;
}
.md-upload-btn:hover {
  background: var(--surface-3, var(--border));
  color: var(--text);
}
.md-upload-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.mark-input-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px;
  background: var(--surface-2);
  border-radius: 10px;
}

.mark-input-row label {
  font-weight: 600;
}

.mark-input-row input[type="number"] {
  flex: 1;
  min-width: 0;
  padding: 10px 12px;
  min-height: var(--tap);
  border: 1.5px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-variant-numeric: tabular-nums;
}

.grade-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.grade-btn {
  padding: 12px 4px;
  min-height: var(--tap);
  border-radius: 12px;
  border: 1.5px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-weight: 600;
  font-size: 0.95rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  line-height: 1.1;
}

.grade-btn .sub-label {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
}

.grade-btn.again {
  border-color: var(--wrong);
  color: var(--wrong);
}
.grade-btn.hard {
  border-color: #d98b2b;
  color: #c87515;
}
@media (prefers-color-scheme: dark) {
  .grade-btn.hard {
    color: #f5b964;
  }
}
.grade-btn.good {
  border-color: var(--accent);
  color: var(--accent);
}
.grade-btn.easy {
  border-color: var(--correct);
  color: var(--correct);
}

/* Suggested-grade highlight: glow + thicker accent ring */
.grade-btn.suggested {
  border-width: 2.5px;
  box-shadow:
    0 0 0 3px color-mix(in srgb, currentColor 22%, transparent),
    0 1px 8px color-mix(in srgb, currentColor 28%, transparent);
  transform: translateY(-1px);
}

/* Grade delta row — shows prev → new and the change */
.grade-delta-row {
  display: flex;
  align-items: baseline;
  gap: 10px;
  flex-wrap: wrap;
  padding: 10px 12px;
  background: var(--surface-2);
  border-radius: 10px;
  font-variant-numeric: tabular-nums;
  font-size: 0.95rem;
}

.grade-delta-row .delta-label {
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
}

.grade-delta-row .delta-prev {
  color: var(--text-muted);
}

.grade-delta-row .delta-arrow {
  color: var(--text-muted);
}

.grade-delta-row .delta-new {
  color: var(--text);
  font-weight: 700;
  font-size: 1.05rem;
}

.grade-delta-row .delta-change {
  font-weight: 600;
  margin-left: 2px;
}

.grade-delta-row.delta-up .delta-change {
  color: var(--correct);
}

.grade-delta-row.delta-down .delta-change {
  color: var(--wrong);
}

.grade-delta-row .delta-time {
  margin-left: auto;
  font-size: 0.78rem;
  color: var(--text-muted);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 8px;
}

/* Submit-mark button row (text question flow) */
.submit-row {
  display: flex;
  justify-content: stretch;
}

.submit-mark-btn {
  width: 100%;
  min-height: var(--tap);
  border-radius: 12px;
  border: 1.5px solid var(--accent);
  background: var(--accent);
  color: var(--accent-fg);
  font-weight: 700;
  font-size: 1rem;
  padding: 12px;
}

.submit-mark-btn[disabled] {
  opacity: 0.45;
  cursor: not-allowed;
}

.done-card {
  text-align: center;
  padding: 28px 20px;
}

.done-card h2 {
  font-size: 1.4rem;
  color: var(--text);
  text-transform: none;
  letter-spacing: normal;
  margin-bottom: 8px;
}

/* Focus visibility */
button:focus-visible,
input:focus-visible,
.radio-group label:focus-within {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ---------- Phase 4b — Builder UI ---------- */

/* Status badge used on pack rows and the pack-edit status pill.
   Variants: draft, published, flagged, archived. */
.status-badge {
  display: inline-block;
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  font-weight: 600;
  margin-left: 6px;
  vertical-align: middle;
}
.status-badge.draft {
  background: var(--surface-2);
  color: var(--text-muted);
}
.status-badge.published {
  background: var(--correct-bg);
  color: var(--correct);
}
.status-badge.flagged {
  background: var(--wrong-bg);
  color: var(--wrong);
}
.status-badge.archived {
  background: var(--surface-2);
  color: var(--text-muted);
  opacity: 0.6;
}

/* Inputs and textareas inside the builder settings cards. Match the
   sign-in input treatment so focus rings are consistent. */
.settings input[type="text"],
.settings textarea {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  min-height: var(--tap);
  padding: 12px 14px;
  font-size: 16px; /* prevent iOS zoom on focus */
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  outline: none;
  font-family: inherit;
  margin-top: 4px;
}
.settings textarea {
  min-height: 80px;
  resize: vertical;
  line-height: 1.4;
}
.settings input[type="text"]:focus,
.settings textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(53, 88, 212, 0.18);
}

/* Pack-edit action button row — wraps on narrow viewports. */
.pack-edit-actions,
.question-edit-actions {
  display: flex;
  gap: 8px;
  margin-top: 16px;
  flex-wrap: wrap;
}

/* Rows inside the pack-edit questions list are smaller than admin rows
   because they only need name + remove button. */
.pack-edit-question-main {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 0.9rem;
}
.pack-edit-question-meta {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 2px;
  text-transform: none;
  letter-spacing: 0;
}

/* ---------- Phase 4c — Question editor ---------- */

.settings select {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  min-height: var(--tap);
  padding: 12px 14px;
  font-size: 16px;
  color: var(--text);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  outline: none;
  margin-top: 4px;
}
.settings select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(53, 88, 212, 0.18);
}

/* Live parts-tree preview that updates as the author types. */
#question-edit-parts-preview {
  margin-top: 8px;
  padding: 10px 12px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-muted);
  white-space: pre-wrap;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 12px;
  line-height: 1.45;
  min-height: 44px;
}
#question-edit-parts-preview.has-error {
  color: var(--wrong);
  border-color: var(--wrong);
}
#question-edit-parts-preview .parts-preview-total {
  display: block;
  color: var(--text);
  font-weight: 600;
  margin-bottom: 4px;
}

/* Packs checklist — rows of pack name + checkbox. */
#question-edit-packs-checklist {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 6px;
}
.pack-checkbox-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.9rem;
}
.pack-checkbox-row input[type="checkbox"] {
  accent-color: var(--accent);
  width: 18px;
  height: 18px;
}
.pack-checkbox-row .pack-checkbox-name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}