:root {
  color-scheme: light;
  --army-green: #4B5320;
  --army-green-dark: #3a4019;
  --army-green-light: #5c6530;
  --ink: #1a1a1a;
  --muted: #5c5c5c;
  --line: #d4d0c4;
  --bg: #f5f4f0;
  --panel: #ffffff;
  --gold: #C9A227;
  --gold-light: #e8d48a;
  --accent: var(--gold);
  --brand: var(--army-green);
  --brand-dark: #0d0d0d;
  --ok: #2d6a4f;
  --focus: #C9A227;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Helvetica Neue", Arial, system-ui, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  font-size: 16px;
}

a { color: var(--army-green); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.shell { min-height: 100vh; }

/* —— Top bar (army.mod.uk pattern: dark bar, bold wordmark) —— */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 0 28px;
  min-height: 56px;
  background: var(--brand-dark);
  border-bottom: 4px solid var(--army-green);
  position: sticky;
  top: 0;
  z-index: 50;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  font-size: 20px;
  color: #fff;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 12px 0;
}

.brand:hover { text-decoration: none; color: #fff; }

.brand-mark {
  width: 8px;
  height: 32px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--army-green) 100%);
  flex-shrink: 0;
}

.nav {
  display: flex;
  gap: 4px;
  align-items: center;
  flex-wrap: wrap;
}

.nav a, .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 40px;
  padding: 8px 14px;
  border-radius: 0;
  border: 1px solid transparent;
  background: transparent;
  color: var(--ink);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.06em;
  cursor: pointer;
  font-family: inherit;
}

.topbar .nav a {
  color: rgba(255,255,255,0.92);
  border-color: transparent;
}

.topbar .nav a:hover {
  background: rgba(75,83,32,0.55);
  text-decoration: none;
}

.btn:hover, .nav a.btn:hover {
  text-decoration: none;
  background: var(--army-green-light);
}

.btn.primary, .topbar .nav .btn.primary {
  background: var(--army-green);
  border-color: var(--army-green);
  color: #fff;
}

.btn.primary:hover { background: var(--army-green-light); }

.btn.dark {
  background: var(--brand-dark);
  border-color: var(--brand-dark);
  color: #fff;
}

.btn.gold {
  background: var(--gold);
  border-color: var(--gold);
  color: var(--brand-dark);
}

.wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding: 32px 24px;
}

/* —— Hero —— */
.home-hero {
  min-height: 560px;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: 32px;
  align-items: end;
  padding: 72px max(24px, calc((100vw - 1180px) / 2)) 40px;
  background:
    linear-gradient(135deg, rgba(13,13,13,0.94) 0%, rgba(75,83,32,0.88) 100%),
    repeating-linear-gradient(-45deg, transparent, transparent 8px, rgba(201,162,39,0.04) 8px, rgba(201,162,39,0.04) 16px);
  color: #fff;
}

.hero-copy { max-width: 780px; }

.eyebrow {
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  font-weight: 800;
  margin: 0 0 12px;
}

.home-hero .eyebrow { color: var(--gold-light); }

.home-hero h1, .page-title h1 {
  font-size: clamp(36px, 6vw, 72px);
  line-height: 1;
  margin: 0 0 20px;
  max-width: 900px;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  font-weight: 800;
}

.lead {
  font-size: 18px;
  color: var(--muted);
  max-width: 720px;
  margin: 0;
}

.home-hero .lead {
  color: rgba(255,255,255,0.88);
  font-size: 19px;
  line-height: 1.55;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.hero-ops {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.hero-ops div, .tool-card, .panel, .card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 0;
}

.hero-ops div {
  padding: 20px;
  color: var(--ink);
  border-left: 4px solid var(--gold);
}

.hero-ops span {
  display: block;
  font-size: 28px;
  font-weight: 800;
  color: var(--army-green);
  text-transform: uppercase;
}

.hero-ops strong {
  font-size: 11px;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.intro-band, .split-section, .section-head {
  display: grid;
  grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
  gap: 32px;
  align-items: start;
}

.intro-band h2, .split-section h2, .section-head h2 {
  font-size: clamp(26px, 4vw, 42px);
  line-height: 1.05;
  margin: 0;
  text-transform: uppercase;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.tool-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}

.tool-card {
  padding: 20px;
  min-height: 168px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  color: var(--ink);
  border-left: 4px solid var(--army-green);
  transition: background 0.15s;
}

.tool-card:hover {
  text-decoration: none;
  background: #fff;
  border-left-color: var(--gold);
}

.tool-card span { font-weight: 800; color: var(--gold); font-size: 13px; }
.tool-card strong { font-size: 18px; line-height: 1.15; text-transform: uppercase; }
.tool-card small { color: var(--muted); font-size: 14px; line-height: 1.4; }

.split-section {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  margin: 24px 0;
  padding: 32px 0;
}

.feature-list { display: grid; gap: 12px; }

.feature-list article {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 16px;
  padding: 18px;
  border-left: 4px solid var(--army-green);
  background: #fff;
}

.feature-list strong { text-transform: uppercase; font-size: 13px; letter-spacing: 0.04em; }

.section-head {
  grid-template-columns: 1fr auto;
  align-items: end;
  margin-bottom: 20px;
}

.page-title { padding: 8px 0 20px; }
.page-title h1 { font-size: clamp(32px, 5vw, 56px); }

.panel { padding: 24px; background: var(--panel); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 14px;
}

.card {
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  color: var(--ink);
  border-left: 4px solid var(--army-green);
  background: #fff;
  transition: border-color 0.15s;
}

.card:hover {
  text-decoration: none;
  border-left-color: var(--gold);
}

.price { min-height: 220px; }
.price strong { font-size: 22px; }
.price .btn { margin-top: auto; }

.meta { font-size: 13px; color: var(--muted); }

.pill {
  display: inline-flex;
  width: max-content;
  border: 1px solid var(--line);
  padding: 4px 10px;
  font-size: 11px;
  color: var(--army-green);
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: rgba(75,83,32,0.06);
}

/* —— PHAK lessons —— */
.phak-hero {
  background: var(--brand-dark);
  color: #fff;
  padding: 48px 24px;
  border-bottom: 4px solid var(--gold);
}

.phak-hero .wrap { padding-top: 0; padding-bottom: 0; }

.phak-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 24px;
}

.phak-card {
  background: #fff;
  border-left: 4px solid var(--army-green);
  padding: 22px;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 200px;
}

.phak-card:hover { text-decoration: none; border-left-color: var(--gold); }

.phak-card .lesson-num {
  font-size: 32px;
  font-weight: 800;
  color: var(--gold);
  line-height: 1;
}

.common-parts {
  margin-top: 40px;
  border-top: 2px solid var(--army-green);
  padding-top: 32px;
}

.common-parts h2 {
  text-transform: uppercase;
  font-weight: 800;
  font-size: 28px;
  margin: 0 0 24px;
}

.common-section {
  margin-bottom: 28px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--line);
}

.common-section:last-child { border-bottom: 0; }

.common-section h3 {
  font-size: 18px;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--army-green);
  margin: 0 0 12px;
}

.lesson-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 24px;
}

.side {
  position: sticky;
  top: 72px;
  align-self: start;
  max-height: calc(100vh - 96px);
  overflow: auto;
}

.list { list-style: none; margin: 0; padding: 0; }

.list a {
  display: block;
  padding: 10px 12px;
  border-left: 3px solid transparent;
  color: var(--ink);
  font-size: 14px;
}

.list a:hover, .list a.active {
  background: rgba(75,83,32,0.08);
  text-decoration: none;
  border-left-color: var(--army-green);
}

.article { padding: 28px 32px; }

.lesson-toolbar {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 20px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
}

.lesson-content h2 {
  font-size: 20px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--army-green);
  margin: 32px 0 12px;
  padding-top: 8px;
  border-top: 1px solid var(--line);
}

.lesson-content h2:first-of-type { border-top: 0; margin-top: 0; }

.lesson-content p, .lesson-content li { max-width: 68ch; }

.lesson-content ul, .lesson-content ol { padding-left: 1.4em; }

.lesson-content code {
  background: rgba(75,83,32,0.1);
  padding: 2px 6px;
  font-size: 0.92em;
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 14px;
  margin: 12px 0;
}

.data-table th, .data-table td {
  padding: 10px 12px;
  border: 1px solid var(--line);
  text-align: left;
}

.data-table th {
  background: var(--army-green);
  color: #fff;
  font-weight: 700;
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.05em;
}

.data-table tr:nth-child(even) td { background: rgba(75,83,32,0.04); }

.lesson-diagram {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 16px 0;
  border: 1px solid var(--line);
}

.print-header {
  display: none;
}

/* —— Legacy lesson content —— */
.legacy-content table { max-width: 100%; width: auto !important; }

.legacy-content img[src*="logo"],
.legacy-content img[src*="Logo"],
.legacy-content img[src*="packshot"],
.legacy-content img[src*="soft_newlogo"],
.legacy-content img[alt*="Teach"],
.legacy-content img[alt*="teach"] {
  display: none !important;
}

.legacy-content img {
  display: block;
  max-width: 100%;
  height: auto;
  max-height: 480px;
  object-fit: contain;
  margin: 14px auto;
  border: 1px solid var(--line);
  background: #fff;
  padding: 8px;
}

.legacy-content, .legacy-content span, .legacy-content p, .legacy-content td {
  color: var(--ink) !important;
  font-family: inherit !important;
  font-size: 16px !important;
}

.form { max-width: 440px; margin: 40px auto; padding: 24px; }

.field { display: grid; gap: 6px; margin-bottom: 14px; }

.field input, .field select, .form-grid input, .form-grid select,
.weather-controls input, .wb-row input {
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 0;
  padding: 10px 12px;
  font: inherit;
  background: #fff;
}

.notice {
  padding: 14px 16px;
  border-left: 4px solid var(--ok);
  background: #eef6f1;
  color: #1e5631;
}

.danger {
  border-left-color: #a4161a;
  background: #fdf2f2;
  color: #7f1d1d;
}

.table { width: 100%; border-collapse: collapse; }
.table th, .table td { padding: 10px; border-bottom: 1px solid var(--line); text-align: left; }

.tools-page { max-width: 1240px; }

.tools-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.tool-panel h2 { margin-top: 0; text-transform: uppercase; font-size: 18px; color: var(--army-green); }
.tool-panel.wide { grid-column: 1 / -1; }

.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.form-grid label, .weather-controls label {
  display: grid;
  gap: 5px;
  font-weight: 700;
  font-size: 11px;
  text-transform: uppercase;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
  margin-top: 16px;
}

.result-grid div, .brief-line {
  background: rgba(75,83,32,0.06);
  border-left: 4px solid var(--army-green);
  padding: 12px;
}

.result-grid span, .brief-line span {
  display: block;
  font-size: 10px;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 800;
  letter-spacing: 0.05em;
}

.result-grid strong, .brief-line strong { font-size: 20px; color: var(--ink); }

.wb-table { display: grid; gap: 8px; }
.wb-head, .wb-row {
  display: grid;
  grid-template-columns: minmax(140px, 1fr) 100px 100px 42px;
  gap: 8px;
  align-items: center;
}

.wb-head {
  font-size: 10px;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 800;
}

.icon-btn {
  min-height: 44px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--army-green);
  font-weight: 800;
  cursor: pointer;
}

.weather-controls { display: flex; gap: 12px; align-items: end; flex-wrap: wrap; }
.weather-controls label { min-width: 180px; }
.weather-output { display: grid; gap: 10px; margin-top: 14px; }

.weather-output pre {
  white-space: pre-wrap;
  background: var(--brand-dark);
  color: #f5f4f0;
  padding: 16px;
  overflow: auto;
  font-size: 13px;
}

.track-tabs{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:24px}
.track-tabs a{padding:10px 16px;border:1px solid var(--line);background:#fff;font-weight:700;font-size:12px;text-transform:uppercase;letter-spacing:.05em;color:var(--ink)}
.track-tabs a:hover{text-decoration:none;background:rgba(75,83,32,.08)}
.track-tabs a.active{background:var(--army-green);border-color:var(--army-green);color:#fff}
.diagram-block{margin:16px 0;padding:12px;background:rgba(75,83,32,.04);border:1px solid var(--line)}
.diagram-block svg{display:block;max-width:100%;height:auto;margin:0 auto}
.lesson-actions-bar{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}
.exam-start-form{display:flex;flex-direction:column;gap:12px;margin-top:auto}

@media (max-width: 900px) {
  .home-hero, .intro-band, .split-section, .section-head, .tools-grid, .phak-grid {
    grid-template-columns: 1fr;
  }
  .tool-strip { grid-template-columns: repeat(2, 1fr); }
  .hero-ops { grid-template-columns: 1fr 1fr; }
  .feature-list article { grid-template-columns: 1fr; }
}

@media (max-width: 620px) {
  .topbar { align-items: flex-start; flex-direction: column; padding: 12px 16px; }
  .wrap { padding: 20px 16px; }
  .home-hero { min-height: auto; grid-template-columns: 1fr; padding: 48px 16px 28px; }
  .home-hero h1 { font-size: 32px; }
  .tool-strip, .hero-ops, .form-grid { grid-template-columns: 1fr; }
  .lesson-layout { grid-template-columns: 1fr; }
  .side { position: relative; top: auto; max-height: none; }
  .wb-head { display: none; }
  .wb-row { grid-template-columns: 1fr; }
  .section-head { align-items: start; }
}

.track-tabs { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 20px; }
.track-tabs a { padding: 10px 16px; border: 1px solid var(--line); border-radius: 4px; font-weight: 800; text-transform: uppercase; font-size: 12px; color: var(--ink); background: #fff; }
.track-tabs a.active, .track-tabs a:hover { background: var(--brand-dark); border-color: var(--brand-dark); color: #fff; text-decoration: none; }
.list a.active { background: #eee7d7; font-weight: 800; }
.lesson-toolbar { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; }
.lesson-actions-bar { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 24px; }
.lesson-content h2 { margin-top: 1.4em; text-transform: uppercase; font-size: 1.1rem; }
.lesson-content ul { padding-left: 1.2em; }
.diagram-block { margin: 16px 0; padding: 12px; background: #eee7d7; border-left: 5px solid var(--brand); }
.diagram-block svg { max-width: 100%; height: auto; display: block; }
.exam-start-form { display: grid; gap: 12px; margin-top: auto; }
.exam-start-form .field { margin: 0; }
.exam-progress { font-size: 13px; font-weight: 800; text-transform: uppercase; color: var(--muted); margin-bottom: 10px; }
.exam-question p { font-size: 18px; }
.exam-options { display: grid; gap: 8px; margin: 16px 0; }
.exam-option { display: flex; gap: 10px; align-items: flex-start; padding: 12px; border: 1px solid var(--line); border-radius: 4px; background: #fff; cursor: pointer; }
.exam-option.correct { border-color: var(--ok); background: #eef8f2; }
.exam-option.wrong { border-color: var(--accent); background: #fff0f1; }
.exam-score { font-size: 42px; font-weight: 900; margin: 0 0 8px; }
.exam-review { display: grid; gap: 12px; margin-top: 16px; }
.review-card { padding: 14px; border-left: 5px solid var(--accent); background: #fff; border: 1px solid var(--line); }
.review-card .explain { color: var(--muted); margin-top: 8px; }
.print-header, .print-footer { display: none; }
.wb-print-sheet { display: none; }

@media print {
  .topbar, .no-print, .lesson-toolbar, .side { display: none !important; }
  body { background: #fff; color: #000; }
  .wrap, .lesson-layout { max-width: none; padding: 0; }
  .lesson-layout { grid-template-columns: 1fr; }
  .panel.article { border: none; box-shadow: none; padding: 0; }
  .print-header, .print-footer { display: block; }
  .print-header { border-bottom: 3px solid #111; margin-bottom: 16px; padding-bottom: 8px; }
  .print-footer { margin-top: 24px; font-size: 11px; color: #444; border-top: 1px solid #ccc; padding-top: 8px; }
  .lesson-content h2 { page-break-after: avoid; }
  .wb-print-sheet { display: block !important; }
  .tools-page .tool-panel:not(#weight-balance) { display: none !important; }
  #weight-balance .wb-table, #weight-balance [data-add-row], #weight-balance .icon-btn { display: none !important; }
}