/* Structoo — light theme, blue accent */

:root {
  --bg: #fafbfc;
  --surface: #ffffff;
  --text: #1a2332;
  --text-muted: #5c6b7f;
  --brand: #1e5a96;
  --brand-hover: #164a7a;
  --border: #e2e8f0;
  --shadow: 0 1px 3px rgba(26, 35, 50, 0.06);
  --radius: 8px;
  --font: "Source Sans 3", "Segoe UI", system-ui, sans-serif;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.5;
}

a {
  color: var(--brand);
  text-decoration: none;
}

a:hover {
  color: var(--brand-hover);
  text-decoration: underline;
}

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header__inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.nav-brand {
  font-weight: 700;
  font-size: 1.35rem;
  letter-spacing: -0.02em;
}

.nav-brand a {
  color: var(--text);
  text-decoration: none;
}

.nav-brand a:hover {
  color: var(--brand);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  flex: 1;
  justify-content: center;
  flex-wrap: wrap;
}

.nav-item {
  position: relative;
}

.nav-item > button {
  font: inherit;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text);
  background: transparent;
  border: none;
  padding: 0.5rem 0.85rem;
  border-radius: var(--radius);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav-item > button::after {
  content: "";
  border: 4px solid transparent;
  border-top-color: var(--text-muted);
  margin-top: 0.25rem;
}

.nav-item:hover > button,
.nav-item:focus-within > button {
  background: var(--bg);
  color: var(--brand);
}

.dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  min-width: 220px;
  margin: 0;
  padding: 0.35rem 0;
  list-style: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: 0 8px 24px rgba(26, 35, 50, 0.1);
}

.nav-item:hover .dropdown,
.nav-item:focus-within .dropdown {
  display: block;
}

.dropdown a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
}

.dropdown a:hover {
  background: var(--bg);
  color: var(--brand);
  text-decoration: none;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.25rem 3rem;
}

.hero {
  text-align: center;
  padding: 2rem 0 1rem;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin: 0 0 0.75rem;
}

.hero p {
  color: var(--text-muted);
  max-width: 36rem;
  margin: 0 auto 1.5rem;
  font-size: 1.05rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  box-shadow: var(--shadow);
}

.card h2 {
  margin: 0 0 0.75rem;
  font-size: 1.15rem;
}

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

.tool-links li {
  border-bottom: 1px solid var(--border);
}

.tool-links li:last-child {
  border-bottom: none;
}

.tool-links a {
  display: block;
  padding: 0.65rem 0;
  font-weight: 500;
}

/* AISC shapes tool */
.tool-page h1 {
  font-size: 1.65rem;
  margin: 0 0 0.5rem;
}

.tool-page .lede {
  color: var(--text-muted);
  margin: 0 0 1.5rem;
  max-width: 42rem;
}

.filters {
  display: grid;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

@media (min-width: 640px) {
  .filters {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 900px) {
  .filters {
    grid-template-columns: repeat(3, 1fr);
  }
}

.filter-field label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.filter-field input,
.filter-field select {
  width: 100%;
  font: inherit;
  padding: 0.5rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
}

.filter-field input:focus,
.filter-field select:focus {
  outline: 2px solid var(--brand);
  outline-offset: 1px;
}

.filter-row-nums {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
}

.status-bar {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.status-bar.error {
  color: #b42318;
}

.table-wrap {
  overflow: auto;
  max-height: min(70vh, 640px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
}

.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.data-table th,
.data-table td {
  padding: 0.5rem 0.65rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.data-table th {
  position: sticky;
  top: 0;
  background: #f1f5f9;
  font-weight: 600;
  cursor: pointer;
  user-select: none;
  z-index: 1;
}

.data-table th:hover {
  background: #e2e8f0;
}

.data-table th.sort-asc::after {
  content: " \2191";
  opacity: 0.7;
}

.data-table th.sort-desc::after {
  content: " \2193";
  opacity: 0.7;
}

.data-table tbody tr:hover {
  background: var(--bg);
}

.data-table .num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.loading {
  padding: 2rem;
  text-align: center;
  color: var(--text-muted);
}

.prose {
  max-width: 40rem;
}

.prose h1 {
  font-size: 1.65rem;
  margin-top: 0;
}

.prose h2 {
  font-size: 1.15rem;
  margin-top: 1.75rem;
}

.prose ul {
  padding-left: 1.25rem;
}

.site-footer {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
  text-align: center;
}

/* Landing */
.landing-hero {
  text-align: center;
  padding: 2.5rem 0 2rem;
  border-radius: var(--radius);
  background: linear-gradient(180deg, #ffffff 0%, var(--bg) 100%);
  border: 1px solid var(--border);
  margin-bottom: 2rem;
}

.landing-hero h1 {
  font-size: clamp(1.85rem, 4.5vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin: 0 0 0.75rem;
  color: var(--text);
}

.landing-hero .tagline {
  color: var(--brand);
  font-weight: 600;
  font-size: 1rem;
  margin: 0 0 1rem;
}

.landing-hero p {
  color: var(--text-muted);
  max-width: 32rem;
  margin: 0 auto;
  font-size: 1.05rem;
}

.tool-grid {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1fr;
}

@media (min-width: 640px) {
  .tool-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.tool-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.35rem;
  box-shadow: var(--shadow);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.tool-card:hover {
  border-color: #c5d9ed;
  box-shadow: 0 4px 16px rgba(30, 90, 150, 0.08);
}

.tool-card h3 {
  margin: 0 0 0.5rem;
  font-size: 1.05rem;
}

.tool-card p {
  margin: 0 0 0.85rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.tool-card a {
  font-weight: 600;
  font-size: 0.9rem;
}

/* Calculator tools */
.calc-form {
  display: grid;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

@media (min-width: 560px) {
  .calc-form.cols-2 {
    grid-template-columns: repeat(2, 1fr);
  }
}

.calc-field label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
}

.calc-field .hint {
  display: block;
  font-size: 0.75rem;
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

.calc-field input,
.calc-field select {
  width: 100%;
  max-width: 20rem;
  font: inherit;
  padding: 0.5rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
}

.calc-field input:focus,
.calc-field select:focus {
  outline: 2px solid var(--brand);
  outline-offset: 1px;
}

.btn-row {
  margin-top: 0.5rem;
}

.btn-primary {
  font: inherit;
  font-weight: 600;
  padding: 0.55rem 1.25rem;
  border: none;
  border-radius: 6px;
  background: var(--brand);
  color: #fff;
  cursor: pointer;
}

.btn-primary:hover {
  background: var(--brand-hover);
}

.results-block {
  margin-top: 1.25rem;
  padding: 1.15rem 1.25rem;
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  border-left: 4px solid var(--brand);
}

.results-block h3 {
  margin: 0 0 0.65rem;
  font-size: 1rem;
}

.results-block dl {
  margin: 0;
  display: grid;
  gap: 0.35rem 1rem;
}

@media (min-width: 480px) {
  .results-block dl {
    grid-template-columns: auto 1fr;
  }
}

.results-block dt {
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.results-block dd {
  margin: 0;
  font-variant-numeric: tabular-nums;
}

.eq-block {
  margin: 0.75rem 0 0;
  padding: 0.65rem 0.85rem;
  background: var(--surface);
  border-radius: 6px;
  font-family: ui-monospace, "Cascadia Code", monospace;
  font-size: 0.82rem;
  line-height: 1.45;
  overflow-x: auto;
  white-space: pre-wrap;
  word-break: break-word;
}

.tool-disclaimer {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
  max-width: 42rem;
}

.prose.wide {
  max-width: 46rem;
}

/* Calculation package report (screen preview; print rules in print.css) */
.calc-report-host {
  margin-top: 1.5rem;
  padding: 1.25rem 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.calc-report-host[hidden] {
  display: none !important;
}

.calc-report-sheet__header {
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--brand);
}

.calc-report-sheet__brand {
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--brand);
}

.calc-report-sheet__title {
  margin: 0.35rem 0 0.25rem;
  font-size: 1.25rem;
  font-weight: 700;
}

.calc-report-sheet__meta-line {
  margin: 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.calc-report-sheet__section-title {
  margin: 1.25rem 0 0.5rem;
  font-size: 0.95rem;
  font-weight: 700;
}

.calc-report-sheet__table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

.calc-report-sheet__table th,
.calc-report-sheet__table td {
  border: 1px solid var(--border);
  padding: 0.4rem 0.55rem;
  text-align: left;
  vertical-align: top;
}

.calc-report-sheet__table thead th {
  background: #f1f5f9;
  font-weight: 600;
}

.calc-report-sheet__table--meta th {
  width: 8.5rem;
  background: #f8fafc;
  font-weight: 600;
}

.calc-report-sheet__equations {
  margin: 0;
  padding: 0.75rem 1rem;
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: ui-monospace, "Cascadia Code", monospace;
  font-size: 0.8rem;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
}

.calc-report-sheet__disclaimer {
  margin-top: 1.5rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
  font-size: 0.75rem;
  color: var(--text-muted);
}

.calc-report-sheet__disclaimer p {
  margin: 0 0 0.5rem;
}

.calc-report-sheet__disclaimer p:last-child {
  margin-bottom: 0;
}

.calc-report-package-heading {
  margin: 0 0 0.25rem;
  font-size: 1rem;
  font-weight: 700;
}