/* =============================================
   Year 10 Mathematics - Unit 1 Theme
   Financial Mathematics, Indices and Measurement
   NESA Stage 5 Core + Paths | 2022 Syllabus
   ============================================= */

:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  --border: #dde3ee;
  --primary: #2563eb;
  --primary-mid: #1d4ed8;
  --primary-light: #dbeafe;
  --accent: #4f46e5;
  --accent-dark: #4338ca;
  --accent-light: #e0e7ff;
  --amber: #d97706;
  --amber-light: #fffbeb;
  --green: #16a34a;
  --green-light: #dcfce7;
  --coral: #e11d48;
  --coral-light: #ffe4e6;
  --radius: 16px;
  --radius-sm: 12px;
  --radius-xs: 10px;
  --shadow: 0 4px 16px rgba(15,23,42,0.04);
}

body { font-family: 'DM Sans',sans-serif; background: var(--bg); color: var(--text); line-height: 1.65; }
h1,h2,h3,h4,h5,h6 { font-family: 'Nunito',sans-serif; font-weight: 700; }
code,.mono,.katex { font-family: 'DM Mono',monospace; }

.skip-link { position: absolute; top: -40px; left: 0; background: var(--primary); color: #fff; padding: 8px 16px; z-index: 100; transition: top 0.3s; }
.skip-link:focus { top: 0; }

.progress-bar-wrap { position: fixed; top: 0; left: 0; right: 0; height: 4px; background: rgba(0,0,0,0.06); z-index: 50; }
.progress-bar-fill { height: 100%; background: linear-gradient(90deg,var(--primary),var(--accent)); width: 0%; transition: width 0.2s ease; }

.section-nav { position: fixed; right: 18px; top: 50%; transform: translateY(-50%); display: flex; flex-direction: column; gap: 8px; z-index: 40; }
.section-nav a { width: 10px; height: 10px; border-radius: 50%; background: var(--border); transition: all 0.2s; }
.section-nav a.active { background: var(--primary); transform: scale(1.3); }
@media (max-width:900px) { .section-nav { display: none; } }

.hero { background: linear-gradient(135deg,#0f172a 0%,#1e3a5f 50%,var(--primary) 100%); color: #fff; padding: 48px 42px 42px; border-radius: 0 0 var(--radius) var(--radius); margin-bottom: 8px; }
.hero-top { display: flex; justify-content: space-between; align-items: flex-start; gap: 20px; max-width: 1100px; margin: 0 auto; }
.hero h1 { color: #fff; font-size: 40px; line-height: 1.08; margin: 0 0 12px; letter-spacing: -0.5px; }
.hero-desc { color: rgba(255,255,255,0.92); font-size: 17px; max-width: 720px; line-height: 1.6; margin: 0; }
.hero-badge-row { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.badge { font-size: 12px; font-weight: 600; padding: 5px 14px; border-radius: 999px; background: rgba(255,255,255,0.14); color: #fff; border: 1px solid rgba(255,255,255,0.22); backdrop-filter: blur(4px); }
.hero-emoji { font-size: 64px; line-height: 1; flex-shrink: 0; }

.crumb { display: flex; gap: 8px; flex-wrap: wrap; font-size: 13px; color: rgba(255,255,255,0.7); margin-bottom: 16px; }
.crumb a { color: rgba(255,255,255,0.85); text-decoration: none; transition: color 0.2s; }
.crumb a:hover { color: #fff; }
.crumb .cur { color: #fff; font-weight: 700; }

.phase-strip { display: flex; align-items: center; justify-content: center; gap: 10px; margin: 12px 0 28px; flex-wrap: wrap; }
.phase-btn { padding: 10px 24px; border-radius: 999px; border: 1px solid var(--border); background: var(--surface); font-size: 13px; font-weight: 600; color: var(--text-light); cursor: pointer; transition: all .2s ease; font-family: 'DM Sans',sans-serif; }
.phase-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); box-shadow: 0 4px 12px rgba(37,99,235,0.25); }
.phase-btn:hover:not(.active) { border-color: var(--primary); color: var(--primary); }
.phase-btn:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }
.phase-arrow { color: var(--text-light); font-size: 12px; opacity: 0.5; }

.page { max-width: 1100px; margin: 0 auto; padding: 0 24px 60px; }

.card { background: var(--surface); border-radius: var(--radius); border: 1px solid var(--border); padding: 28px 32px; margin-bottom: 20px; box-shadow: var(--shadow); }
.card h2 { margin: 0 0 14px; font-size: 22px; color: var(--text); }
.card h3 { margin: 24px 0 10px; font-size: 17px; color: var(--text); }
.card p { margin: 0 0 12px; line-height: 1.65; color: var(--text-muted); }

.think-first { background: linear-gradient(135deg,var(--primary-light) 0%,#eff6ff 100%); border: 1px solid #bfdbfe; border-radius: var(--radius); padding: 24px 28px; margin-bottom: 20px; }
.think-first h2,.think-first h3 { color: var(--primary-mid); margin: 0 0 10px; }
.tf-label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.6px; font-weight: 700; color: var(--primary-mid); margin-bottom: 8px; }
.tf-note { font-size: 13px; color: var(--text-light); font-style: italic; margin-top: 10px; }

.answer-wrap { position: relative; }
.answer-instruction { font-size: 13px; color: var(--text-light); margin: 0 0 8px; }
.answer-textarea { width: 100%; min-height: 80px; padding: 12px 16px; border-radius: var(--radius-xs); border: 1px solid var(--border); font-family: 'DM Sans',sans-serif; font-size: 14px; resize: vertical; background: #fff; color: var(--text); box-sizing: border-box; }
.answer-textarea:focus { outline: 2px solid var(--primary-light); border-color: var(--primary); }
.answer-book-placeholder { display: none; padding: 20px; background: #f8fafc; border-radius: var(--radius-xs); border: 2px dashed var(--border); text-align: center; color: var(--text-light); font-size: 14px; }
.autosave-indicator { font-size: 11px; color: var(--green); margin-top: 6px; opacity: 0; transition: opacity 0.3s; }
.autosave-indicator.visible { opacity: 1; }

.mode-banner { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 24px; margin-bottom: 20px; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
.mode-banner p { margin: 0; font-size: 14px; color: var(--text-muted); }
.mode-toggle { display: flex; gap: 8px; }
.mode-btn { padding: 8px 18px; border-radius: var(--radius-xs); border: 1px solid var(--border); background: #fff; font-size: 13px; font-weight: 600; color: var(--text-light); cursor: pointer; transition: all .2s; font-family: 'DM Sans',sans-serif; }
.mode-btn.active { background: var(--primary); color: #fff; border-color: var(--primary); }
.mode-btn:hover:not(.active) { border-color: var(--primary); color: var(--primary); }

.intention-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px 28px; margin-bottom: 20px; }
.intentions-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(220px,1fr)); gap: 14px; }
.intention-box { background: #f8fafc; border-radius: var(--radius-xs); padding: 16px 18px; border: 1px solid var(--border); }
.intention-box h4 { margin: 0 0 8px; font-size: 13px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--primary); }
.intention-box ul { margin: 0; padding-left: 18px; font-size: 14px; color: var(--text-muted); }
.intention-box li { margin-bottom: 4px; }

.success-criteria { background: linear-gradient(135deg,#ccfbf1 0%,#f0fdfa 100%); border: 1px solid #99f6e4; border-radius: var(--radius); padding: 20px 24px; margin-bottom: 20px; }
.success-criteria h3 { color: var(--teal); margin: 0 0 10px; font-size: 16px; }
.success-criteria ul { margin: 0; padding-left: 20px; font-size: 14px; color: var(--text-muted); }

.key-terms { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px 26px; margin-bottom: 20px; }
.terms-grid { display: grid; grid-template-columns: repeat(auto-fill,minmax(260px,1fr)); gap: 12px; }
.term-item { background: #f8fafc; border-radius: var(--radius-xs); padding: 12px 14px; border: 1px solid var(--border); }
.term-item strong { color: var(--text); font-size: 14px; }
.term-item span { color: var(--text-muted); font-size: 13px; }

.formula-panel { background: linear-gradient(135deg,var(--accent-light) 0%,#eef2ff 100%); border: 1px solid #c7d2fe; border-radius: var(--radius); padding: 24px 28px; margin-bottom: 20px; }
.formula-panel h2,.formula-panel h3 { color: var(--accent-dark); margin: 0 0 14px; }
.formula-box { background: #fff; border-radius: var(--radius-xs); padding: 16px 20px; border: 1px solid #c7d2fe; margin: 12px 0; font-size: 15px; }
.formula-box .label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.5px; color: var(--accent-dark); font-weight: 700; margin-bottom: 8px; }
.formula-box .katex { font-size: 1.05em; }

.misconception { background: var(--amber-light); border: 1px solid #fcd34d; border-radius: var(--radius); padding: 22px 26px; margin-bottom: 20px; }
.misconception h2,.misconception h3 { color: var(--amber); margin: 0 0 14px; }
.miscon-row { display: flex; gap: 12px; margin: 10px 0; align-items: flex-start; }
.miscon-row .icon { width: 28px; height: 28px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 14px; flex-shrink: 0; margin-top: 2px; }
.miscon-row .x-icon { background: var(--coral-light); color: var(--coral); }
.miscon-row .tick-icon { background: var(--green-light); color: var(--green); }
.miscon-row p { margin: 0; font-size: 14px; color: var(--text-muted); line-height: 1.55; }

.activity-card { background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: var(--radius); padding: 22px 26px; margin-bottom: 20px; }
.activity-card h2,.activity-card h3 { color: #15803d; margin: 0 0 12px; }

.worked-example { background: #f8fafc; border-radius: var(--radius-sm); padding: 20px 22px; border: 1px solid #e2e8f0; margin: 14px 0; }
.worked-example .we-label { font-size: 11px; font-weight: 700; text-transform: uppercase; color: var(--primary); margin-bottom: 10px; letter-spacing: 0.4px; }
.worked-example .we-step { display: flex; gap: 10px; margin: 8px 0; font-size: 14px; color: var(--text-muted); }
.worked-example .we-step-num { width: 22px; height: 22px; border-radius: 50%; background: var(--primary-light); color: var(--primary); font-size: 11px; font-weight: 700; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
.worked-example .katex { font-size: 1.02em; }

.example-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 16px 0; }
.example-box { background: #f8fafc; border-radius: var(--radius-sm); padding: 16px; border: 1px solid #e2e8f0; }
.example-box .ex-label { font-size: 11px; font-weight: 700; text-transform: uppercase; color: var(--primary); margin-bottom: 6px; letter-spacing: 0.4px; }
.example-box p { margin: 0; font-size: 14px; color: var(--text-muted); line-height: 1.55; }

.callout { border-radius: var(--radius-sm); padding: 16px 18px; margin: 14px 0; border-left: 4px solid; }
.callout p { margin: 0; font-size: 14px; }
.callout strong { color: var(--text); }
.callout-realworld { background: #f0f9ff; border-color: var(--primary); }
.callout-important { background: var(--amber-light); border-color: var(--amber); }
.callout-scope { background: #f3f4f6; border-color: var(--text-light); }

.interactive-wrap { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; margin: 20px 0; }
.interactive-wrap h3 { margin: 0 0 12px; font-size: 16px; color: var(--text); }
.interactive-frame { width: 100%; border: none; border-radius: var(--radius-sm); background: #f8fafc; min-height: 320px; }

.practice-card { background: var(--green-light); border: 1px solid #86efac; border-radius: var(--radius); padding: 22px 26px; margin-bottom: 20px; }
.practice-card h3 { color: var(--green); margin: 0 0 12px; }

.copy-box { background: linear-gradient(135deg,#f8fafc 0%,#f1f5f9 100%); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 24px; margin-bottom: 20px; }
.copy-box h3 { margin: 0 0 12px; font-size: 16px; color: var(--text); }
.copy-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(200px,1fr)); gap: 12px; }
.copy-item { background: #fff; border-radius: var(--radius-xs); padding: 14px 16px; border: 1px solid var(--border); font-size: 14px; color: var(--text-muted); }
.copy-item strong { color: var(--text); display: block; margin-bottom: 4px; }

.revisit { background: linear-gradient(135deg,var(--primary-light) 0%,#eff6ff 100%); border: 1px solid #bfdbfe; border-radius: var(--radius); padding: 22px 26px; margin-bottom: 20px; }
.revisit h3 { color: var(--primary-mid); margin: 0 0 10px; }
.revisit p { color: var(--text-muted); font-size: 14px; }

.btn { display: inline-flex; align-items: center; gap: 6px; padding: 10px 20px; border-radius: var(--radius-xs); background: var(--primary); color: #fff; font-size: 14px; font-weight: 600; text-decoration: none; border: none; cursor: pointer; transition: all .2s ease; font-family: 'DM Sans',sans-serif; }
.btn:hover { background: var(--primary-mid); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(37,99,235,0.2); }
.btn-outline { background: #fff; color: var(--primary); border: 1.5px solid var(--primary); }
.btn-outline:hover { background: var(--primary-light); }

.worksheet-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 24px; margin-bottom: 20px; display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; }
.worksheet-card h2 { margin: 0; font-size: 16px; }
.worksheet-actions { display: flex; gap: 10px; }

.phase { display: none; }
.phase.active { display: block; }

.mcq-option { display: flex; align-items: flex-start; gap: 12px; padding: 14px 16px; border-radius: var(--radius-xs); border: 1px solid var(--border); background: #fff; margin-bottom: 10px; cursor: pointer; transition: all .2s; }
.mcq-option:hover { border-color: var(--primary); background: var(--primary-light); }
.mcq-option input[type='radio'] { margin-top: 3px; accent-color: var(--primary); }
.mcq-option.correct { border-color: var(--green); background: var(--green-light); }
.mcq-option.incorrect { border-color: var(--coral); background: var(--coral-light); }
.mcq-feedback { font-size: 13px; color: var(--text-muted); margin-top: 8px; padding: 10px 14px; border-radius: 8px; background: #f8fafc; display: none; }
.mcq-feedback.visible { display: block; }

.sa-question { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 24px; margin-bottom: 16px; }
.sa-question h4 { margin: 0 0 8px; font-size: 15px; color: var(--text); }
.sa-meta { font-size: 12px; color: var(--text-light); margin-bottom: 12px; }
.sa-marks { display: inline-block; padding: 2px 8px; border-radius: 4px; background: var(--primary-light); color: var(--primary-mid); font-weight: 600; font-size: 11px; }

.accordion { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; margin-bottom: 16px; }
.accordion-header { padding: 14px 18px; background: #f8fafc; cursor: pointer; display: flex; justify-content: space-between; align-items: center; font-weight: 600; font-size: 14px; color: var(--text); transition: background .2s; }
.accordion-header:hover { background: #f1f5f9; }
.accordion-body { padding: 18px 20px; display: none; font-size: 14px; color: var(--text-muted); line-height: 1.65; }
.accordion.open .accordion-body { display: block; }

.completion-wrap { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px 24px; margin: 24px 0; display: flex; align-items: center; gap: 12px; }
.completion-wrap input[type='checkbox'] { width: 20px; height: 20px; accent-color: var(--green); cursor: pointer; }
.completion-wrap label { font-size: 14px; font-weight: 600; color: var(--text); cursor: pointer; }

.nav-footer { display: flex; justify-content: space-between; align-items: center; padding: 24px 0; border-top: 1px solid var(--border); margin-top: 30px; }
.nav-link { display: flex; align-items: center; gap: 8px; color: var(--text-light); text-decoration: none; font-size: 14px; transition: color .2s; }
.nav-link:hover { color: var(--primary); }

.game-wrap { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; text-align: center; margin-bottom: 20px; }
.game-wrap h3 { margin: 0 0 12px; font-size: 18px; }
.game-frame { width: 100%; border: none; border-radius: var(--radius-sm); min-height: 500px; }

.section-label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.6px; font-weight: 700; color: var(--text-light); margin: 28px 0 10px; }
.path-badge { display: inline-block; padding: 3px 10px; border-radius: 999px; background: var(--amber-light); color: var(--amber); font-size: 11px; font-weight: 700; text-transform: uppercase; letter-spacing: 0.3px; }

.bloom-badge { display: inline-block; padding: 3px 10px; border-radius: 999px; font-size: 11px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.3px; }
.bloom-remember { background: #f3f4f6; color: #374151; }
.bloom-understand { background: #dbeafe; color: #1e40af; }
.bloom-apply { background: #dcfce7; color: #166534; }
.bloom-analyse { background: #fef3c7; color: #92400e; }
.bloom-evaluate { background: #ffe4e6; color: #9f1239; }

@media (max-width:640px) {
  .hero { padding: 32px 24px; }
  .hero h1 { font-size: 28px; }
  .hero-top { flex-direction: column; }
  .hero-emoji { font-size: 48px; }
  .page { padding: 0 16px 48px; }
  .card { padding: 22px 20px; }
  .example-grid { grid-template-columns: 1fr; }
  .intentions-grid { grid-template-columns: 1fr; }
  .terms-grid { grid-template-columns: 1fr; }
  .mode-banner { flex-direction: column; align-items: flex-start; }
  .worksheet-card { flex-direction: column; align-items: flex-start; }
  .nav-footer { flex-direction: column; gap: 12px; align-items: flex-start; }
}

@media (prefers-reduced-motion:reduce) {
  *,*::before,*::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}

.katex { font-size: 1.08em; }
.katex-display { margin: 1em 0; overflow-x: auto; }