/* ============================================
   CLARTUTORS DESIGN TOKENS (CSS Variables)
   ============================================ */
:root {
  /* Colors */
  --brand-primary: #F0D9EF;
  --brand-secondary: #CDE9DC;
  --brand-accent: #FFE6BB;
  --brand-dark: #021E40;
  --brand-pink: #FCDCE1;
  --brand-sage: #E9ECCE;
  --brand-sky: #C4DFE5;
  --brand-primary-dark: #B8A9D4;
  --brand-secondary-dark: #7BB59A;
  --text-secondary: #54595F;
  --text-tertiary: #69727D;
  --bg-white: #FFFFFF;
  --bg-light: #F8F9FA;
  --border-default: #E8E9EB;
  --answer-line: #D0D5DB;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(2,30,64,0.08);
  --shadow-md: 0 4px 12px rgba(2,30,64,0.1);

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;

  /* Typography */
  --font-heading: 'Poppins', sans-serif;
  --font-body: 'Roboto', sans-serif;
}

/* ============================================
   RESET & BASE
   ============================================ */
* { margin:0; padding:0; box-sizing:border-box; }
body {
  font-family: var(--font-body);
  background: var(--bg-light);
  color: var(--brand-dark);
  line-height: 1.7;
  padding: 20px;
  font-size: 15px;
}
.container { max-width: 820px; margin: 0 auto; }

/* ============================================
   HEADER COMPONENT
   Usage: <div class="header">...</div>
   ============================================ */
.header {
  background: linear-gradient(135deg, var(--brand-primary), var(--brand-sky));
  padding: 28px 36px;
  border-radius: 12px;
  margin-bottom: 24px;
  display: flex;
  align-items: center;
  gap: 18px;
  border-bottom: 3px solid var(--brand-primary-dark);
  box-shadow: var(--shadow-md);
}
.header-logo {
  width: 56px; height: 56px;
  object-fit: contain;
  border-radius: 50%;
  background: rgba(255,255,255,0.7);
  padding: 4px;
  flex-shrink: 0;
}
.header-content h1 {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 26px;
  color: var(--brand-dark);
  line-height: 1.2;
}
.header-content .sub {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: 2px;
}
.header-content .meta {
  font-size: 12px;
  color: var(--text-tertiary);
  margin-top: 4px;
}
.header-creds {
  margin-left: auto;
  text-align: right;
  font-size: 11px;
  color: var(--text-secondary);
  line-height: 1.5;
}
.header-creds a {
  color: var(--brand-primary-dark);
  text-decoration: none;
  font-weight: 600;
}

/* ============================================
   STUDENT INFO BAR
   Usage: <div class="student-info">...</div>
   ============================================ */
.student-info {
  background: var(--bg-white);
  border: 2px solid var(--border-default);
  border-radius: 10px;
  padding: 16px 24px;
  margin-bottom: 24px;
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  box-shadow: var(--shadow-sm);
}
.student-info label {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 11px;
  color: var(--brand-dark);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}
.student-info .field { flex: 1; min-width: 140px; }
.student-info input {
  width: 100%; border: none;
  border-bottom: 1.5px solid var(--border-default);
  padding: 5px 0; font-size: 14px; outline: none;
  font-family: var(--font-body);
}
.student-info input:focus { border-bottom-color: var(--brand-primary-dark); }

/* ============================================
   INSTRUCTION BOX
   Usage: <div class="instruction-box">...</div>
   ============================================ */
.instruction-box {
  background: var(--brand-accent);
  border-left: 4px solid #F0C040;
  border-radius: 8px;
  padding: 12px 18px;
  margin-bottom: 24px;
  font-size: 13px;
  line-height: 1.6;
}
.instruction-box strong { color: var(--brand-dark); }

/* ============================================
   KEY CONCEPTS BOX
   Usage: <div class="concept-box">...</div>
   ============================================ */
.concept-box {
  background: linear-gradient(135deg, var(--brand-sage), var(--brand-secondary));
  border: 1.5px solid var(--brand-secondary-dark);
  border-radius: 10px;
  padding: 12px 18px;
  margin-bottom: 24px;
  font-size: 13px;
}
.concept-box h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--brand-dark);
  margin-bottom: 4px;
  font-size: 14px;
}
.concept-box ul { padding-left: 18px; }
.concept-box li { margin-bottom: 2px; }

/* ============================================
   SECTION HEADER
   Usage: <div class="section-header">...</div>
   ============================================ */
.section { margin-bottom: 32px; }
.section-header {
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 18px;
  padding-bottom: 8px;
  border-bottom: 3px solid var(--brand-primary);
}
.section-badge {
  background: var(--brand-primary-dark);
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 11px;
  padding: 3px 12px;
  border-radius: 20px;
}
.section-header h2 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 18px;
  color: var(--brand-dark);
}
.section-header .marks {
  margin-left: auto;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 12px;
  color: var(--brand-primary-dark);
}

/* ============================================
   QUESTION CARD
   Usage: <div class="q-card">...</div>
          <div class="q-card open-ended">...</div> (for open-ended)
   ============================================ */
.q-card {
  background: var(--bg-white);
  border: 1.5px solid var(--border-default);
  border-radius: 10px;
  padding: 20px 24px;
  margin-bottom: 12px;
  border-left: 4px solid var(--brand-secondary-dark);
  box-shadow: var(--shadow-sm);
  page-break-inside: avoid;
}
.q-card.open-ended { border-left-color: var(--brand-primary-dark); }
.q-num {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 13px;
  color: var(--brand-secondary-dark);
  margin-bottom: 4px;
}
.q-card.open-ended .q-num { color: var(--brand-primary-dark); }
.q-text { font-size: 14px; margin-bottom: 10px; line-height: 1.65; }
.q-text p { margin-bottom: 6px; }

/* ============================================
   SUB-QUESTION LIST (Hanging Indent)
   Usage: <ul class="sub-list">...</ul>
          Each item: <li>(a) Question text</li>
   ============================================ */
.sub-list {
  margin-left: 8px;
  padding-left: 0;
  list-style: none;
}
.sub-list li {
  position: relative;
  padding-left: 20px;
  margin-bottom: 4px;
  text-indent: -16px;
  line-height: 1.55;
}

/* ============================================
   DIAGRAM BOX (SVG Container)
   Usage: <div class="diagram-box">...</div>
   ============================================ */
.diagram-box {
  background: var(--bg-light);
  border: 1.5px solid var(--border-default);
  border-radius: 8px;
  padding: 14px;
  margin: 8px 0;
  text-align: center;
  overflow-x: auto;
}
.diagram-box svg { max-width: 100%; height: auto; }

/* ============================================
   FRACTION COMPONENT (Vertical Layout)
   Usage: <span class="frac">
            <span class="num">3</span>
            <span class="den">4</span>
          </span>
   For larger fractions (e.g. in MCQ options):
          <span class="frac frac-big">...</span>
   ============================================ */
.frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  margin: 0 2px;
  font-size: 0.9em;
}
.frac .num, .frac .den {
  display: block;
  text-align: center;
  line-height: 1.2;
  padding: 0 3px;
}
.frac .num { border-bottom: 1.5px solid var(--brand-dark); }
.frac-big { font-size: 1.1em; }

/* ============================================
   ANSWER KEY — Single Column Stacked (DEFAULT)
   Usage: <div class="answer-key">...</div>
          Each item: <div class="answer-key-item">Q1: answer</div>
   ============================================ */
.answer-key { display: block !important; }
.answer-key-item {
  display: block;
  background: var(--brand-secondary);
  padding: 8px 12px;
  border-radius: 8px;
  margin-bottom: 6px;
  font-size: 13px;
  line-height: 1.55;
}

/* ============================================
   ANSWER LINES (Writing Space)
   Usage: <div class="writing-space">...</div>
          Or inline answer lines:
          <div class="answer-line"></div>
   ============================================ */
.writing-space {
  min-height: 60px;
  margin-top: 12px;
  border-bottom: 1px dashed #ccc;
}
.answer-lines { margin-top: 8px; }
.answer-line {
  border-bottom: 1.5px dashed var(--border-default);
  height: 28px;
}

/* ============================================
   DATA TABLE
   Usage: <table class="data-table">...</table>
   ============================================ */
.data-table {
  width: 100%; border-collapse: collapse;
  margin: 8px 0; font-size: 13px;
}
.data-table th {
  background: var(--brand-dark);
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 600;
  padding: 6px 10px;
  text-align: center;
  font-size: 12px;
}
.data-table td {
  border: 1px solid var(--border-default);
  padding: 6px 10px;
  text-align: center;
}
.data-table tr:nth-child(even) { background: #F9F9F9; }

/* ============================================
   BUTTONS (Interactive worksheets only)
   Usage: <div class="btn-row">...</div>
          <button class="btn btn-check">Check</button>
          <button class="btn btn-reset">Reset</button>
          <button class="btn btn-toggle">Show Answers</button>
          <button class="btn btn-print">Print</button>
   ============================================ */
.btn-row { display: flex; gap: 10px; margin: 20px 0; flex-wrap: wrap; }
.btn {
  font-family: var(--font-heading);
  font-weight: 600; font-size: 12px;
  padding: 9px 22px; border: none;
  border-radius: 8px; cursor: pointer;
  transition: transform 0.1s, box-shadow 0.15s;
}
.btn:active { transform: scale(0.97); }
.btn-check { background: var(--brand-secondary-dark); color: #fff; }
.btn-reset { background: var(--brand-dark); color: #fff; }
.btn-toggle { background: var(--brand-primary-dark); color: #fff; }
.btn-print { background: var(--brand-accent); color: var(--brand-dark); }

/* ============================================
   FOOTER
   Usage: <div class="footer">...</div>
   ============================================ */
.footer {
  text-align: center;
  padding: 18px;
  font-size: 11px;
  color: var(--text-tertiary);
  border-top: 1px solid var(--border-default);
  margin-top: 32px;
}
.footer a {
  color: var(--brand-primary-dark);
  text-decoration: none;
  font-weight: 600;
}

/* ============================================
   PRINT STYLES (All worksheets) — A4 optimized
   ============================================ */
@media print {
  @page { size: A4; margin: 12mm 10mm 12mm 10mm; }
  
  body {
    background: #fff !important;
    padding: 0 !important;
    font-size: 12.5px;
    line-height: 1.45;
    color: #000 !important;
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
  }
  
  .container { max-width: 100%; padding: 0 8px; }
  
  /* Hide interactive elements */
  .btn-row, .score-box, #show-answers-btn { display: none !important; }
  .option { cursor: default; }
  
  /* Show answer key in print */
  .answer-key { display: block !important; }
  .answer-key-item { break-inside: avoid; }
  
  /* Prevent awkward page breaks inside content blocks */
  .q-card, .diagram-box, .concept-box, .instruction-box,
  .student-info, .header, .section-header,
  .s-card, .info-bar, .summary-grid {
    page-break-inside: avoid;
    break-inside: avoid;
  }
  
  /* Prevent section headers from being separated from content */
  .section-header {
    page-break-after: avoid;
    break-after: avoid;
  }
  
  /* Ensure header gradient prints correctly */
  .header, .section-badge, .data-table th, .option-letter,
  .s-card::before {
    -webkit-print-color-adjust: exact !important;
    print-color-adjust: exact !important;
  }
  
  /* Tighten spacing for print */
  .q-card { padding: 10px 14px; margin-bottom: 8px; }
  .q-text { font-size: 12.5px; line-height: 1.5; }
  .option { font-size: 12px; padding: 4px 6px; }
  .header { padding: 16px 20px; margin-bottom: 14px; }
  .student-info { padding: 10px 16px; margin-bottom: 14px; }
  
  /* Ensure diagrams don't get cut off */
  .diagram-box { page-break-inside: avoid; break-inside: avoid; }
  .diagram-box svg, .diagram-box img { max-width: 100% !important; height: auto !important; }
  
  /* Footer on last page only */
  .footer { margin-top: 16px; padding: 12px; }
}

/* ============================================
   PAGE BREAK HELPERS
   Usage: <div class="page-break-before"> or <div class="page-break-after">
   ============================================ */
.page-break-before { page-break-before: always; break-before: page; }
.page-break-after { page-break-after: always; break-after: page; }

/* ============================================
   TRIG/REFERENCE PAGE STYLES (MathJax pages)
   Usage: content-section, formula-box, diagram-container, value-table
   ============================================ */
.content-section {
  margin-bottom: 36px;
}
.content-section h2 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 20px;
  color: var(--brand-dark);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 3px solid var(--brand-primary);
}
.content-section p {
  margin-bottom: 12px;
  line-height: 1.7;
}

.formula-box {
  background: linear-gradient(135deg, #e8f4f8, #d6eaf8);
  border-left: 4px solid var(--brand-dark);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 16px 0;
  font-size: 15px;
}

.diagram-container {
  background: var(--bg-white);
  border: 1.5px solid var(--border-default);
  border-radius: 10px;
  padding: 20px;
  margin: 16px 0;
  text-align: center;
  overflow-x: auto;
}
.diagram-container svg {
  max-width: 100%;
  height: auto;
}

.value-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 14px;
}
.value-table th {
  background: var(--brand-dark);
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 600;
  padding: 10px 14px;
  text-align: center;
  border: 1px solid rgba(255,255,255,0.2);
}
.value-table td {
  border: 1px solid var(--border-default);
  padding: 8px 14px;
  text-align: center;
}
.value-table tr:nth-child(even) {
  background: #f9fafb;
}
.highlight-angle {
  color: #c0392b;
  font-weight: 700;
}

.page-header, .page-footer {
  text-align: center;
  padding: 16px;
  font-size: 12px;
  color: var(--text-tertiary);
  border-top: 1px solid var(--border-default);
  margin-top: 32px;
}
.page-header {
  border-top: none;
  border-bottom: 1px solid var(--border-default);
  margin-top: 0;
  margin-bottom: 24px;
}
.page-header h1 {
  font-family: var(--font-heading);
  font-weight: 800;
  font-size: 24px;
  color: var(--brand-dark);
  margin-bottom: 4px;
}
.subtitle {
  font-size: 14px;
  color: var(--text-secondary);
  margin-top: 4px;
}