/* Library — tutor-only curriculum materials (hub + subject browsers + material viewer) */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Inter', sans-serif;
  background: #f5f3ee;
  color: #111111;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* ── Header (matches curriculum.css) ── */

.lib-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #111111;
  padding: 0.875rem clamp(1.25rem, 4vw, 2.5rem);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.lib-logo {
  font-family: 'Playfair Display', serif;
  font-size: 1.1rem;
  color: #fff;
  text-decoration: none;
  letter-spacing: 0.01em;
}

.lib-logo:hover { color: #ddd; }

.lib-header-tag {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: rgba(255,255,255,0.45);
}

/* ── Two-column layout ── */

.lib-layout {
  display: grid;
  grid-template-columns: 272px 1fr;
  min-height: calc(100vh - 56px);
}

/* ── Left nav ── */

.lib-nav {
  background: #1c1c1c;
  border-right: 1px solid #2d2d2d;
  position: sticky;
  top: 56px;
  height: calc(100vh - 56px);
  overflow-y: auto;
  padding: 1.25rem 0 2rem;
  scrollbar-width: thin;
  scrollbar-color: #3a3a3a #1c1c1c;
}

.nav-grade-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: rgba(255,255,255,0.3);
  padding: 0 1.25rem 0.9rem;
}

.nav-domain {
  margin-bottom: 1.25rem;
}

.nav-domain-name {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: rgba(255,255,255,0.4);
  padding: 0.25rem 1.25rem 0.4rem;
}

.nav-cluster-link {
  display: block;
  padding: 0.45rem 1.25rem 0.45rem 1.5rem;
  color: #aaa;
  text-decoration: none;
  font-size: 0.79rem;
  line-height: 1.35;
  border-left: 2px solid transparent;
  transition: color 0.12s, border-color 0.12s;
}

.nav-cluster-link:hover {
  color: #fff;
  border-left-color: #555;
  background: rgba(255,255,255,0.04);
}

.nav-cluster-link.active {
  color: #fff;
  border-left-color: #fff;
  background: rgba(255,255,255,0.07);
}

.nav-cluster-code {
  font-size: 0.67rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: rgba(255,255,255,0.3);
  display: block;
  margin-bottom: 0.1rem;
}

/* ── Full Grade Diagnostic (sidebar placeholder — tests not wired yet) ── */

.nav-diagnostics {
  padding-bottom: 1.1rem;
  margin-bottom: 1.2rem;
  border-bottom: 1px solid #2d2d2d;
}

.diag-sub {
  font-size: 0.63rem;
  color: rgba(255,255,255,0.28);
  letter-spacing: 0.04em;
  padding: 0 1.25rem 0.55rem;
}

.diag-slot-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  padding: 0 1.25rem;
}

.diag-slot {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.28rem 0.5rem;
  border: 1px dashed #3a3a3a;
  border-radius: 6px;
  cursor: default;
  opacity: 0.6;
}

.diag-slot-form {
  font-size: 0.7rem;
  font-weight: 600;
  color: rgba(255,255,255,0.55);
}

.diag-slot-tag {
  font-size: 0.54rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.06rem 0.3rem;
  border-radius: 3px;
}

.diag-sampled { color: #9ec8ff; background: rgba(90,150,230,0.16); }
.diag-new-material { color: #ffd59e; background: rgba(230,170,90,0.16); }

/* ── Main area ── */

.lib-main {
  padding: clamp(1.75rem, 4vw, 3rem) clamp(1.5rem, 4vw, 3rem);
  max-width: 920px;
}

/* Welcome */

.lib-welcome {
  margin-top: 3rem;
}

.lib-welcome h2 {
  font-family: 'Playfair Display', serif;
  font-size: 1.65rem;
  margin-bottom: 0.6rem;
}

.lib-welcome p {
  color: #666;
  font-size: 0.92rem;
}

/* ── Cluster view ── */

.cluster-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 2px solid #e0ddd6;
}

.cluster-breadcrumb {
  font-size: 0.75rem;
  color: #888;
  margin-bottom: 0.35rem;
}

.cluster-title {
  font-family: 'Playfair Display', serif;
  font-size: 1.45rem;
  line-height: 1.25;
  margin-bottom: 0.3rem;
}

.cluster-meta {
  font-size: 0.8rem;
  color: #999;
}

/* Standard cards */

.standard-card {
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 10px;
  padding: 1.1rem 1.35rem;
  margin-bottom: 0.85rem;
}

.std-header {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  margin-bottom: 0.85rem;
}

.std-code {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: #888;
  flex-shrink: 0;
}

.std-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.std-materials {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}

.mat-group {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.mat-group-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: #bbb;
  margin-right: 0.15rem;
}

.mat-chip {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.2rem 0.65rem;
  border-radius: 5px;
  text-decoration: none;
  white-space: nowrap;
}

.mat-chip.unavailable {
  background: #f0efec;
  color: #ccc;
  cursor: default;
}

.chip-lesson  { background: #dbeafe; color: #1e40af; }
.chip-easy    { background: #d1fae5; color: #065f46; }
.chip-med     { background: #fef3c7; color: #92400e; }
.chip-hard    { background: #fee2e2; color: #991b1b; }
.chip-quiz    { background: #f3e8ff; color: #6b21a8; }
.chip-worksheet { background: #d1fae5; color: #065f46; }
.chip-tier1   { background: #d1fae5; color: #065f46; }
.chip-tier2   { background: #fef3c7; color: #92400e; }

.chip-lesson:hover    { background: #bfdbfe; }
.chip-easy:hover      { background: #a7f3d0; }
.chip-med:hover       { background: #fde68a; }
.chip-hard:hover      { background: #fecaca; }
.chip-quiz:hover      { background: #e9d5ff; }
.chip-worksheet:hover { background: #a7f3d0; }
.chip-tier1:hover     { background: #a7f3d0; }
.chip-tier2:hover     { background: #fde68a; }

/* ── Material viewer (material.html) ── */

.material-page {
  padding: clamp(1.75rem, 4vw, 3rem) clamp(1.5rem, 4vw, 3rem);
  max-width: 840px;
  margin: 0 auto;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: #666;
  text-decoration: none;
  font-size: 0.82rem;
  margin-bottom: 1.75rem;
  transition: color 0.12s;
}

.back-link:hover { color: #111; }

.material-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 2px solid #e0ddd6;
}

.material-badges {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin-bottom: 0.6rem;
  flex-wrap: wrap;
}

.badge-type {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 0.22rem 0.6rem;
  border-radius: 4px;
}

.badge-lesson     { background: #dbeafe; color: #1e40af; }
.badge-worksheet  { background: #d1fae5; color: #065f46; }
.badge-quiz       { background: #f3e8ff; color: #6b21a8; }

.badge-difficulty {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 0.22rem 0.6rem;
  border-radius: 4px;
}

.difficulty-easy   { background: #d1fae5; color: #065f46; }
.difficulty-medium { background: #fef3c7; color: #92400e; }
.difficulty-hard   { background: #fee2e2; color: #991b1b; }

.badge-standard {
  font-size: 0.72rem;
  font-weight: 700;
  color: #aaa;
  letter-spacing: 0.04em;
}

.material-title {
  font-family: 'Playfair Display', serif;
  font-size: 1.6rem;
  line-height: 1.2;
  margin-bottom: 0.55rem;
}

.material-intro {
  color: #555;
  font-size: 0.92rem;
  line-height: 1.65;
  max-width: 680px;
}

/* Section headings */

.section-heading {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #999;
  margin: 2rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid #e0ddd6;
}

/* Worked examples */

.worked-example {
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 10px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1.1rem;
}

.example-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #2563eb;
  margin-bottom: 0.55rem;
}

.example-prompt {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 1rem;
  line-height: 1.6;
}

.solution-steps {
  background: #f8f7f4;
  border-left: 3px solid #ddd;
  border-radius: 0 6px 6px 0;
  padding: 0.85rem 1rem 0.85rem 1.1rem;
  margin-bottom: 0.85rem;
}

.solution-steps ol {
  padding-left: 1.15rem;
}

.solution-steps li {
  font-size: 0.9rem;
  color: #333;
  line-height: 1.7;
  margin-bottom: 0.3rem;
}

.solution-steps li:last-child { margin-bottom: 0; }

.example-answer {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: #111;
  color: #fff;
  font-size: 0.83rem;
  font-weight: 600;
  padding: 0.32rem 0.85rem;
  border-radius: 6px;
}

/* Practice problems */

.practice-item {
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 10px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 0.9rem;
}

.practice-number {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #999;
  margin-bottom: 0.45rem;
}

.practice-prompt {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 0.85rem;
  line-height: 1.6;
}

.toggle-btn {
  background: none;
  border: 1px solid #ddd;
  border-radius: 5px;
  padding: 0.28rem 0.75rem;
  font-size: 0.78rem;
  font-weight: 500;
  color: #666;
  cursor: pointer;
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
  font-family: inherit;
}

.toggle-btn:hover { background: #f0efec; color: #111; border-color: #bbb; }

.toggle-btn.active {
  background: #111;
  color: #fff;
  border-color: #111;
}

.toggle-content { margin-top: 0.65rem; }
.toggle-content.hidden { display: none; }

.hint-text {
  background: #fffbeb;
  border-left: 3px solid #f59e0b;
  border-radius: 0 6px 6px 0;
  padding: 0.65rem 0.9rem;
  font-size: 0.87rem;
  color: #555;
  line-height: 1.55;
}

.answer-box {
  background: #f0fdf4;
  border: 1px solid #a7f3d0;
  border-radius: 6px;
  padding: 0.75rem 1rem;
}

.answer-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: #065f46;
  margin-bottom: 0.25rem;
}

.answer-value {
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.answer-box .solution-steps {
  background: rgba(0,0,0,0.03);
  margin-bottom: 0;
}

/* Worksheet / Quiz problems */

.answer-key-bar {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  margin-bottom: 1.25rem;
}

.answer-key-btn {
  background: #111;
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 0.42rem 1rem;
  font-size: 0.81rem;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.12s;
}

.answer-key-btn:hover { background: #333; }

.worksheet-problems {
  list-style: none;
  display: grid;
  gap: 0.9rem;
}

.worksheet-problem {
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 10px;
  padding: 1.1rem 1.35rem;
}

.problem-number-row {
  display: flex;
  align-items: flex-start;
  gap: 0.85rem;
}

.problem-num {
  font-weight: 700;
  font-size: 0.85rem;
  color: #bbb;
  min-width: 1.35rem;
  flex-shrink: 0;
  padding-top: 0.1rem;
}

.problem-prompt {
  font-size: 0.97rem;
  line-height: 1.65;
  flex: 1;
}

.problem-difficulty-tag {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  padding: 0.15rem 0.5rem;
  border-radius: 4px;
  margin-bottom: 0.5rem;
}

.answer-key-block {
  margin-top: 0.85rem;
  padding-top: 0.75rem;
  border-top: 1px dashed #e0ddd6;
}

.answer-key-block.hidden { display: none; }

.ak-answer {
  font-size: 0.88rem;
  font-weight: 700;
  color: #065f46;
  margin-bottom: 0.4rem;
}

.ak-steps {
  padding-left: 1.2rem;
  margin-top: 0.35rem;
}

.ak-steps li {
  font-size: 0.83rem;
  color: #444;
  line-height: 1.6;
  margin-bottom: 0.2rem;
}

/* Stub notice */

.stub-notice {
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: 8px;
  padding: 0.65rem 1rem;
  font-size: 0.81rem;
  color: #78350f;
  margin-bottom: 1.35rem;
}

/* Loading / error */

.hidden { display: none; }

.mat-loading,
.mat-error {
  padding: 4rem 2rem;
  text-align: center;
  color: #888;
}

.mat-error h2 {
  font-family: 'Playfair Display', serif;
  color: #111;
  margin-bottom: 0.5rem;
}

/* ── Hub page (library/index.html) ── */

.hub-main {
  max-width: 900px;
  margin: 0 auto;
  padding: clamp(2rem, 5vw, 4rem) clamp(1.25rem, 4vw, 2.5rem);
}

.hub-header {
  margin-bottom: 3rem;
}

.hub-header h1 {
  font-family: 'Playfair Display', serif;
  font-size: clamp(1.75rem, 4vw, 2.4rem);
  margin-bottom: 0.6rem;
}

.hub-subtitle {
  color: #555;
  font-size: 0.95rem;
  max-width: 580px;
  line-height: 1.6;
}

.hub-sections {
  display: flex;
  flex-direction: column;
  gap: 3.5rem;
}

.hub-section h2 {
  font-family: 'Playfair Display', serif;
  font-size: 1.4rem;
  margin-bottom: 0.35rem;
}

.hub-section-desc {
  color: #666;
  font-size: 0.85rem;
  line-height: 1.55;
  margin-bottom: 1.75rem;
  max-width: 560px;
}

.hub-grade-group {
  margin-bottom: 1.5rem;
}

.hub-grade-group h3 {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: #999;
  margin-bottom: 0.65rem;
}

.hub-grade-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.hub-grade-btn {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 0.6rem 1.1rem;
  border-radius: 8px;
  font-size: 0.88rem;
  font-weight: 500;
  text-decoration: none;
  min-width: 100px;
  text-align: center;
  line-height: 1.3;
  transition: background 0.12s, border-color 0.12s, transform 0.1s;
}

.hub-grade-btn.soon {
  background: #f0efec;
  color: #bbb;
  border: 1px solid #e8e5e0;
  cursor: default;
}

.hub-grade-btn.live {
  background: #fff;
  color: #111;
  border: 1.5px solid #111;
  font-weight: 600;
  gap: 0.35rem;
}

.hub-grade-btn.live:hover {
  background: #111;
  color: #fff;
  transform: translateY(-1px);
}

.hub-live-tag {
  font-size: 0.62rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: #059669;
  background: #d1fae5;
  padding: 0.1rem 0.45rem;
  border-radius: 3px;
}

.hub-grade-btn.live:hover .hub-live-tag {
  background: rgba(255,255,255,0.2);
  color: #fff;
}

.hub-grade-btn.hs-btn {
  min-width: 130px;
}

.hs-course {
  font-weight: 600;
}

.hs-grade {
  font-size: 0.72rem;
  opacity: 0.6;
}

.cluster-test-section {
  margin-top: 2rem;
}

.cluster-test-card {
  border-style: dashed;
  background: #fafaf8;
}

.cluster-test-desc {
  font-size: 0.8rem;
  color: #888;
  margin-top: 0.1rem;
}

.chip-cluster-worksheet { background: #374151; color: #fff; }
.chip-cluster-worksheet:hover { background: #4b5563; }
.chip-cluster-test { background: #111; color: #fff; }
.chip-cluster-test:hover { background: #333; }

.hub-note {
  margin-top: 3rem;
  padding: 0.9rem 1.1rem;
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 8px;
  font-size: 0.83rem;
  color: #666;
  line-height: 1.55;
}

/* ── Quiz items ── */
.quiz-problems {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.quiz-problem {
  background: #fff;
  border: 1px solid #e0ddd6;
  border-radius: 10px;
  padding: 1.25rem 1.5rem;
}

.quiz-question-row {
  display: flex;
  gap: 0.75rem;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.quiz-options {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  margin-left: 1.75rem;
}

.quiz-option {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 1rem;
  background: #fafaf8;
  border: 1.5px solid #e8e6e1;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.93rem;
  color: #333;
  transition: background 0.15s, border-color 0.15s;
}

.quiz-option:hover { background: #eeece7; border-color: #bbb; }

.quiz-option-letter {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.5rem;
  height: 1.5rem;
  min-width: 1.5rem;
  background: #e0ddd7;
  border-radius: 50%;
  font-size: 0.72rem;
  font-weight: 700;
  color: #666;
}

.quiz-opt-correct { background: #d4edda !important; border-color: #28a745 !important; color: #155724 !important; }
.quiz-opt-correct .quiz-option-letter { background: #28a745; color: #fff; }

.quiz-opt-wrong { background: #f8d7da !important; border-color: #dc3545 !important; color: #721c24 !important; }
.quiz-opt-wrong .quiz-option-letter { background: #dc3545; color: #fff; }

.quiz-feedback {
  margin: 0.75rem 0 0 1.75rem;
  font-size: 0.88rem;
  font-weight: 600;
}
.quiz-feedback.hidden { display: none; }
.quiz-fb-correct { color: #28a745; }
.quiz-fb-wrong   { color: #dc3545; }

.ak-steps-wrap {
  margin: 0.75rem 0 0 1.75rem;
  padding: 0.75rem 1rem;
  background: #f5f3ee;
  border-radius: 6px;
  font-size: 0.85rem;
  color: #555;
}
.ak-steps-wrap.hidden { display: none; }
.ak-steps-wrap ol { padding-left: 1.25rem; }