/* Mechanical Statics Interactive Companion — Dr. Kay Rand Morgan */
:root {
  --bg: #0b1220;
  --bg-elev: #121b2e;
  --bg-soft: #17233a;
  --bg-muted: #0f1729;
  --line: rgba(148, 163, 184, 0.16);
  --line-strong: rgba(148, 163, 184, 0.28);
  --text: #e8eef8;
  --text-dim: #9fb0c9;
  --text-mute: #6f829d;
  --accent: #3ecf8e;
  --accent-2: #4cc9f0;
  --accent-3: #f4b942;
  --danger: #ff6b7a;
  --warn: #f0a202;
  --card: rgba(18, 27, 46, 0.92);
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.35);
  --radius: 18px;
  --radius-sm: 12px;
  --header-h: 72px;
  --font: "DM Sans", system-ui, sans-serif;
  --display: "Outfit", "DM Sans", system-ui, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
  --max: 1180px;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background:
    radial-gradient(1200px 600px at 10% -10%, rgba(62, 207, 142, 0.12), transparent 55%),
    radial-gradient(900px 500px at 90% 0%, rgba(76, 201, 240, 0.10), transparent 50%),
    var(--bg);
  min-height: 100vh;
  line-height: 1.55;
}

img, canvas { max-width: 100%; display: block; }

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: #042015;
  padding: 0.6rem 1rem;
  z-index: 1000;
}
.skip-link:focus { left: 1rem; top: 1rem; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px);
  background: rgba(11, 18, 32, 0.82);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  max-width: var(--max);
  margin: 0 auto;
  min-height: var(--header-h);
  padding: 0 1.25rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: inherit;
  text-decoration: none;
  min-width: 0;
}
.brand:hover { text-decoration: none; }

.brand-mark {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  font-family: var(--mono);
  font-weight: 700;
  font-size: 0.95rem;
  color: #042015;
  background: linear-gradient(135deg, var(--accent), #7ee0b0);
  box-shadow: 0 0 0 1px rgba(62, 207, 142, 0.35), 0 8px 24px rgba(62, 207, 142, 0.25);
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}
.brand-text strong {
  font-family: var(--display);
  font-size: 0.98rem;
  font-weight: 700;
}
.brand-text small {
  color: var(--text-dim);
  font-size: 0.75rem;
}

.primary-nav {
  display: flex;
  align-items: center;
  gap: 0.15rem;
  margin-left: 0.5rem;
  flex-wrap: wrap;
}
.primary-nav a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  padding: 0.45rem 0.7rem;
  border-radius: 999px;
  transition: 0.15s ease;
}
.primary-nav a:hover,
.primary-nav a.active {
  color: var(--text);
  background: rgba(255, 255, 255, 0.06);
  text-decoration: none;
}

.header-meta { margin-left: auto; }
.author-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.75rem;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  background: rgba(76, 201, 240, 0.08);
  color: var(--accent-2);
  font-size: 0.82rem;
  font-weight: 600;
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-elev);
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  cursor: pointer;
}
.nav-toggle span {
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
}

/* Views */
.view { display: none; }
.view.active { display: block; animation: fadeIn 0.28s ease; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

/* Hero */
.hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, transparent, var(--bg) 95%),
    repeating-linear-gradient(90deg, rgba(148,163,184,0.05) 0 1px, transparent 1px 48px),
    repeating-linear-gradient(0deg, rgba(148,163,184,0.05) 0 1px, transparent 1px 48px);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  max-width: var(--max);
  margin: 0 auto;
  padding: 3.5rem 1.25rem 3rem;
  display: grid;
  grid-template-columns: 1.2fr 0.9fr;
  gap: 2rem;
  align-items: start;
}

.eyebrow {
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 700;
  margin: 0 0 0.85rem;
}

.hero h1 {
  font-family: var(--display);
  font-size: clamp(2.1rem, 4.5vw, 3.4rem);
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin: 0 0 1rem;
  font-weight: 800;
}
.hero h1 span {
  background: linear-gradient(90deg, var(--accent-2), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.lead {
  font-size: 1.08rem;
  color: var(--text-dim);
  max-width: 52ch;
  margin: 0 0 1rem;
}

.credit-line {
  margin: 0 0 1.5rem;
  color: var(--text);
  font-size: 1.05rem;
}
.credit-line strong {
  color: var(--accent-3);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

.btn {
  appearance: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: 999px;
  padding: 0.75rem 1.2rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  transition: 0.15s ease;
  text-decoration: none;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn:active { transform: none; }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #2db87a);
  color: #042015;
  box-shadow: 0 10px 28px rgba(62, 207, 142, 0.28);
}
.btn-primary:hover { filter: brightness(1.05); }

.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--line-strong);
}
.btn-ghost:hover { background: rgba(255,255,255,0.05); }

.btn-sm {
  padding: 0.45rem 0.85rem;
  font-size: 0.85rem;
}

.hero-stats {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.75rem;
}
.hero-stats li {
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 0.85rem 0.7rem;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.hero-stats strong {
  font-family: var(--display);
  font-size: 1.25rem;
  color: var(--accent-2);
}
.hero-stats span {
  font-size: 0.78rem;
  color: var(--text-mute);
}

.promise-card {
  background: var(--card);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
  box-shadow: var(--shadow);
}
.promise-card h2 {
  margin: 0 0 0.5rem;
  font-family: var(--display);
  font-size: 1.2rem;
}
.promise-card > p {
  color: var(--text-dim);
  margin: 0 0 1rem;
  font-size: 0.95rem;
}

.method-steps {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--text);
  font-size: 0.92rem;
}
.method-steps li { margin-bottom: 0.45rem; }
.method-steps li::marker { color: var(--accent); font-weight: 700; }

/* Sections */
.section-pad {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2.75rem 1.25rem;
}
.section-pad.muted {
  max-width: none;
  background: rgba(255,255,255,0.02);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.section-pad.muted > * {
  max-width: var(--max);
  margin-left: auto;
  margin-right: auto;
}

.section-head {
  margin-bottom: 1.5rem;
}
.section-head h2 {
  font-family: var(--display);
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  margin: 0 0 0.4rem;
  letter-spacing: -0.02em;
}
.section-head p {
  margin: 0;
  color: var(--text-dim);
  max-width: 60ch;
}

/* Roadmap */
.roadmap {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.9rem;
}
.road-card {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 1rem 1.05rem;
  transition: 0.15s ease;
}
.road-card:hover {
  border-color: rgba(62, 207, 142, 0.4);
  transform: translateY(-2px);
}
.road-card .weeks {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 600;
}
.road-card h3 {
  margin: 0.35rem 0 0.3rem;
  font-size: 1rem;
  font-family: var(--display);
}
.road-card p {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.88rem;
}

/* Use cards */
.use-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}
.use-card {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
}
.use-num {
  font-family: var(--mono);
  color: var(--accent-2);
  font-weight: 700;
  font-size: 0.85rem;
}
.use-card h3 {
  margin: 0.5rem 0 0.4rem;
  font-family: var(--display);
  font-size: 1.05rem;
}
.use-card p {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* Chapters */
.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
}
.chapter-card {
  text-align: left;
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
  color: inherit;
  cursor: pointer;
  transition: 0.15s ease;
  font: inherit;
  width: 100%;
}
.chapter-card:hover,
.chapter-card.active {
  border-color: rgba(76, 201, 240, 0.45);
  box-shadow: 0 0 0 1px rgba(76, 201, 240, 0.15), var(--shadow);
  transform: translateY(-2px);
}
.chapter-card .ch-num {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--accent-2);
  font-weight: 600;
}
.chapter-card h3 {
  margin: 0.4rem 0 0.45rem;
  font-family: var(--display);
  font-size: 1.15rem;
}
.chapter-card p {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.9rem;
}

.chapter-detail {
  background: var(--bg-elev);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}
.chapter-detail h2 {
  font-family: var(--display);
  margin: 0 0 0.35rem;
}
.chapter-detail .promise {
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 1rem;
}
.detail-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 1.5rem;
}
.detail-block h3 {
  font-family: var(--display);
  font-size: 1rem;
  margin: 0 0 0.6rem;
  color: var(--accent-2);
}
.detail-block ul, .detail-block ol {
  margin: 0;
  padding-left: 1.15rem;
  color: var(--text-dim);
  font-size: 0.92rem;
}
.detail-block li { margin-bottom: 0.35rem; }
.symbol-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}
.symbol-table th,
.symbol-table td {
  border-bottom: 1px solid var(--line);
  padding: 0.45rem 0.35rem;
  text-align: left;
}
.symbol-table th { color: var(--text-mute); font-weight: 600; }
.symbol-table td:first-child {
  font-family: var(--mono);
  color: var(--accent-3);
  white-space: nowrap;
}

/* Tools */
.tool-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 1.25rem;
}
.tool-tab {
  border: 1px solid var(--line);
  background: var(--bg-elev);
  color: var(--text-dim);
  border-radius: 999px;
  padding: 0.55rem 0.95rem;
  font: inherit;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: 0.15s ease;
}
.tool-tab:hover { color: var(--text); border-color: var(--line-strong); }
.tool-tab.active {
  color: #042015;
  background: linear-gradient(135deg, var(--accent), #2db87a);
  border-color: transparent;
}

.tool-panel {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
}
.tool-panel[hidden] { display: none !important; }

.tool-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  align-items: start;
}
.tool-layout.single { grid-template-columns: 1fr; }

.tool-form h3 {
  margin: 0 0 0.35rem;
  font-family: var(--display);
}
.tool-note {
  margin: 0 0 1rem;
  color: var(--text-mute);
  font-size: 0.88rem;
}
.tool-form label {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  font-size: 0.88rem;
  color: var(--text-dim);
  margin-bottom: 0.75rem;
  font-weight: 500;
}
.tool-form input,
.tool-form select {
  font: inherit;
  font-family: var(--mono);
  background: var(--bg);
  border: 1px solid var(--line-strong);
  color: var(--text);
  border-radius: 10px;
  padding: 0.65rem 0.75rem;
  outline: none;
}
.tool-form input:focus,
.tool-form select:focus {
  border-color: var(--accent-2);
  box-shadow: 0 0 0 3px rgba(76, 201, 240, 0.15);
}

.force-row {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  gap: 0.5rem;
  margin-bottom: 0.55rem;
  align-items: end;
}
.force-row label { margin: 0; }
.force-row .remove-force {
  height: 42px;
  width: 42px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--danger);
  cursor: pointer;
  font-size: 1.1rem;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin: 0.5rem 0 1rem;
}

.tool-result {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: var(--radius-sm);
  background: rgba(62, 207, 142, 0.08);
  border: 1px solid rgba(62, 207, 142, 0.25);
  font-family: var(--mono);
  font-size: 0.9rem;
  line-height: 1.55;
  min-height: 3rem;
  white-space: pre-wrap;
}
.tool-result:empty { display: none; }
.tool-result.warn {
  background: rgba(240, 162, 2, 0.1);
  border-color: rgba(240, 162, 2, 0.35);
}
.tool-result.danger {
  background: rgba(255, 107, 122, 0.1);
  border-color: rgba(255, 107, 122, 0.35);
}

.tool-visual {
  background:
    radial-gradient(circle at center, rgba(76,201,240,0.06), transparent 55%),
    var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 0.75rem;
  display: grid;
  place-items: center;
  min-height: 360px;
}
.tool-visual canvas {
  width: 100%;
  height: auto;
  max-width: 420px;
}

.unit-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem 1rem;
}
.quick-facts {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}
.quick-facts h4 {
  margin: 0 0 0.5rem;
  font-family: var(--display);
}
.quick-facts ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* Formulas */
.formula-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-bottom: 1.25rem;
}
.filter-btn {
  border: 1px solid var(--line);
  background: var(--bg-elev);
  color: var(--text-dim);
  border-radius: 999px;
  padding: 0.45rem 0.85rem;
  font: inherit;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}
.filter-btn.active {
  background: rgba(76, 201, 240, 0.15);
  color: var(--accent-2);
  border-color: rgba(76, 201, 240, 0.4);
}

.formula-list {
  display: grid;
  gap: 0.75rem;
}
.formula-card {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 1rem 1.15rem;
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 1rem;
  align-items: start;
}
.formula-card .tag {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--accent);
  font-weight: 600;
}
.formula-card h3 {
  margin: 0.2rem 0 0;
  font-size: 0.98rem;
  font-family: var(--display);
}
.formula-card .eq {
  font-family: var(--mono);
  font-size: 1rem;
  color: var(--accent-3);
  margin: 0 0 0.35rem;
}
.formula-card .note {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.88rem;
}

/* Practice */
.practice-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 1.25rem;
  align-items: start;
}
.practice-nav {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}
.practice-nav button {
  text-align: left;
  border: none;
  background: transparent;
  color: var(--text-dim);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  padding: 0.7rem 0.8rem;
  border-radius: 10px;
  cursor: pointer;
}
.practice-nav button:hover,
.practice-nav button.active {
  background: rgba(62, 207, 142, 0.12);
  color: var(--text);
}

.practice-main {
  background: var(--bg-elev);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.35rem;
  min-height: 360px;
}
.practice-main .placeholder {
  color: var(--text-mute);
}
.practice-main h3 {
  font-family: var(--display);
  margin: 0 0 0.5rem;
}
.problem-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 1rem;
  margin-bottom: 1rem;
  background: var(--bg);
}
.problem-card p { margin: 0.4rem 0; color: var(--text-dim); }
.problem-card .given {
  font-family: var(--mono);
  font-size: 0.88rem;
  color: var(--accent-2);
}
.answer-box {
  margin-top: 0.75rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}
.answer-box input {
  font-family: var(--mono);
  background: var(--bg-elev);
  border: 1px solid var(--line-strong);
  color: var(--text);
  border-radius: 10px;
  padding: 0.55rem 0.7rem;
  min-width: 140px;
}
.reveal {
  margin-top: 0.6rem;
  padding: 0.75rem;
  border-radius: 10px;
  background: rgba(76, 201, 240, 0.08);
  border: 1px solid rgba(76, 201, 240, 0.25);
  font-family: var(--mono);
  font-size: 0.88rem;
  display: none;
}
.reveal.show { display: block; }
.quiz-options {
  display: grid;
  gap: 0.5rem;
  margin: 0.75rem 0;
}
.quiz-options button {
  text-align: left;
  background: var(--bg);
  border: 1px solid var(--line);
  color: var(--text);
  border-radius: 10px;
  padding: 0.75rem 0.9rem;
  font: inherit;
  cursor: pointer;
}
.quiz-options button:hover { border-color: var(--accent-2); }
.quiz-options button.correct {
  border-color: var(--accent);
  background: rgba(62, 207, 142, 0.12);
}
.quiz-options button.wrong {
  border-color: var(--danger);
  background: rgba(255, 107, 122, 0.1);
}
.score-bar {
  margin-top: 1rem;
  font-weight: 600;
  color: var(--accent-3);
}

/* About */
.about-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 2rem;
}
.about-grid h2 {
  font-family: var(--display);
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  margin: 0 0 0.75rem;
}
.author-card {
  margin-top: 1.75rem;
  display: flex;
  gap: 1rem;
  align-items: center;
  background: var(--bg-elev);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  padding: 1.15rem;
}
.author-avatar {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  display: grid;
  place-items: center;
  font-family: var(--display);
  font-weight: 800;
  font-size: 1.2rem;
  color: #042015;
  background: linear-gradient(135deg, var(--accent-3), #f6d365);
  flex-shrink: 0;
}
.author-card h3 {
  margin: 0 0 0.2rem;
  font-family: var(--display);
}
.author-card p { margin: 0.15rem 0; font-size: 0.92rem; color: var(--text-dim); }
.muted-text { color: var(--text-mute) !important; }

.about-side h3 {
  font-family: var(--display);
  margin: 0 0 0.75rem;
}
.outcome-list {
  margin: 0 0 1.25rem;
  padding-left: 1.15rem;
  color: var(--text-dim);
  font-size: 0.9rem;
}
.outcome-list li { margin-bottom: 0.45rem; }
.notice {
  background: rgba(240, 162, 2, 0.08);
  border: 1px solid rgba(240, 162, 2, 0.3);
  border-radius: var(--radius-sm);
  padding: 1rem;
  font-size: 0.88rem;
  color: var(--text-dim);
}
.notice strong { color: var(--accent-3); }

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 1rem;
  background: rgba(0,0,0,0.2);
}
.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 1.75rem 1.25rem 2.25rem;
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.site-footer p {
  margin: 0.25rem 0 0;
  color: var(--text-dim);
  font-size: 0.9rem;
}
.footer-credit {
  text-align: right;
}
.footer-credit strong {
  color: var(--accent-3);
}

/* Responsive */
@media (max-width: 960px) {
  .hero-grid,
  .detail-grid,
  .tool-layout,
  .about-grid,
  .practice-layout,
  .formula-card {
    grid-template-columns: 1fr;
  }
  .use-grid { grid-template-columns: 1fr 1fr; }
  .hero-stats { grid-template-columns: 1fr 1fr; }
  .footer-credit { text-align: left; }
}

@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .primary-nav {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: rgba(11, 18, 32, 0.98);
    border-bottom: 1px solid var(--line);
    flex-direction: column;
    align-items: stretch;
    padding: 0.75rem;
    margin: 0;
  }
  .primary-nav.open { display: flex; }
  .header-meta { display: none; }
  .use-grid { grid-template-columns: 1fr; }
  .unit-grid { grid-template-columns: 1fr; }
  .force-row { grid-template-columns: 1fr 1fr; }
  .force-row .remove-force { grid-column: span 2; width: 100%; }
}

/* Print */
@media print {
  .site-header, .tool-tabs, .nav-toggle, .hero-actions { display: none !important; }
  body { background: white; color: black; }
  .view { display: block !important; }
}