:root {
    --background: #181a1b;
    --surface: #202324;
    --text: #e8e6e3;
    --muted-text: #b2aca2;
    --border: #3a3f41;
    --primary: #55b7c1;
    --primary-dark: #8bd3da;
    --accent: #173438;
    --shadow: 0 18px 45px rgba(0, 0, 0, 0.28);
    --radius: 18px;
    color-scheme: dark;
}

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    background: var(--background);
    color: var(--text);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
        "Segoe UI", sans-serif;
    line-height: 1.6;
}

a {
    color: var(--primary);
}

.container {
    width: min(1160px, calc(100% - 32px));
    margin-inline: auto;
}

.container.narrow {
    width: min(760px, calc(100% - 32px));
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    border-bottom: 1px solid rgba(58, 63, 65, 0.92);
    background: rgba(24, 26, 27, 0.94);
    backdrop-filter: blur(14px);
}

.nav-wrap {
    min-height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.brand {
    color: var(--text);
    font-size: 1.05rem;
    font-weight: 800;
    text-decoration: none;
}

nav {
    display: flex;
    gap: 22px;
}

nav a {
    color: var(--muted-text);
    font-weight: 650;
    text-decoration: none;
}

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

.hero,
.page-header {
    background:
        radial-gradient(circle at top right, rgba(85, 183, 193, 0.13), transparent 34%),
        linear-gradient(180deg, #1d2021, #181a1b);
}

.hero {
    padding: 92px 0;
}

.page-header {
    padding: 30px 0 0px;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.25fr 0.75fr;
    gap: 56px;
    align-items: center;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1 {
    max-width: 850px;
    margin-bottom: 0px;
    font-size: clamp(2.35rem, 6vw, 4.8rem);
    line-height: 1.04;
    letter-spacing: -0.05em;
}

.page-header h1 {
    font-size: clamp(2.3rem, 5vw, 4rem);
}

h2 {
    margin-bottom: 18px;
    font-size: clamp(1.75rem, 4vw, 2.7rem);
    line-height: 1.15;
    letter-spacing: -0.035em;
}

h3 {
    margin-bottom: 10px;
    font-size: 1.18rem;
}

.lead {
    max-width: 720px;
    color: var(--muted-text);
    font-size: clamp(1.05rem, 2vw, 1.28rem);
}

.eyebrow {
    margin-bottom: 12px;
    color: var(--primary);
    font-size: 0.78rem;
    font-weight: 850;
    letter-spacing: 0.14em;
    text-transform: uppercase;
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 32px;
}

.button {
    display: inline-flex;
    min-height: 48px;
    align-items: center;
    justify-content: center;
    border: 1px solid transparent;
    border-radius: 12px;
    padding: 11px 18px;
    font: inherit;
    font-weight: 800;
    text-decoration: none;
    cursor: pointer;
}

.button.primary {
    background: rgb(12, 61, 66);
    color: #f2f0ed;
}

.button.primary:hover {
    background: rgb(17, 78, 84);
    color: #f2f0ed;
}

.button.secondary {
    border-color: var(--border);
    background: var(--surface);
    color: var(--text);
}

.full-width {
    width: 100%;
}

.hero-panel {
    display: grid;
    gap: 14px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    background: rgba(32, 35, 36, 0.88);
    box-shadow: var(--shadow);
}

.hero-panel div {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    padding: 14px 4px;
}

.hero-panel div:last-child {
    border-bottom: 0;
}

.hero-panel span {
    color: var(--muted-text);
}

.section {
    padding: 10px 0;
}

.section.muted {
    border-block: 1px solid var(--border);
    background: #1c1f20;
}

.section-heading {
    margin-bottom: 30px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.card,
.calculator-card {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    box-shadow: var(--shadow);
}

.card {
    padding: 24px;
}

.card p {
    color: var(--muted-text);
}

.status {
    display: inline-flex;
    margin-bottom: 18px;
    border-radius: 999px;
    padding: 5px 10px;
    background: var(--accent);
    color: var(--primary-dark);
    font-size: 0.76rem;
    font-weight: 850;
    text-transform: uppercase;
}

.status.live {
    border: 1px solid rgba(85, 183, 193, 0.48);
    background: rgba(12, 61, 66, 0.8);
    color: #d9f4f6;
}

.button:disabled {
    cursor: wait;
    opacity: 0.7;
}

.two-column {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 60px;
}

.calculator-card {
    padding: clamp(22px, 5vw, 38px);
}

.form-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 50px minmax(0, 1fr);
    gap: 14px;
    align-items: end;
}

.field {
    margin-bottom: 22px;
}

.field[hidden] {
    display: none;
}

.field label {
    display: block;
    margin-bottom: 8px;
    font-weight: 800;
}

input,
select {
    width: 100%;
    min-height: 50px;
    border: 1px solid #404648;
    border-radius: 11px;
    padding: 10px 12px;
    background: #202324;
    color: var(--text);
    font: inherit;
    color-scheme: dark;
}

input:focus,
select:focus {
    outline: 3px solid rgba(85, 183, 193, 0.20);
    border-color: var(--primary);
}

.swap-wrap {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-bottom: 22px;
}

.swap-button {
    width: 44px;
    height: 44px;
    border: 1px solid var(--border);
    border-radius: 50%;
    background: #202324;
    color: var(--primary);
    font-size: 1.2rem;
    cursor: pointer;
}

.result {
    margin-top: 24px;
    border-radius: 14px;
    padding: 20px;
    background: var(--accent);
}

.result > span {
    display: block;
    color: var(--muted-text);
    font-size: 0.82rem;
    font-weight: 800;
    text-transform: uppercase;
}

.result strong {
    display: block;
    margin-top: 4px;
    color: #f2f0ed;
    font-size: clamp(1.8rem, 5vw, 3rem);
    overflow-wrap: anywhere;
}

.result-unit {
    display: inline;
    margin-left: 0.2em;
    font-size: 0.55em;
    font-weight: 650;
    text-transform: none;
    white-space: nowrap;
}

.alert.error,
.errorlist {
    color: #ff7b72;
}

.errorlist {
    margin: 7px 0 0;
    padding-left: 20px;
}

.material-weight-form {
    margin-bottom: 28px;
}

.material-form-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0 18px;
}

.form-section-heading {
    margin: 12px 0 6px;
    font-size: 1.45rem;
    letter-spacing: -0.02em;
}

.help-text {
    margin-bottom: 20px;
    color: var(--muted-text);
    font-size: 0.95rem;
}

.unit-label {
    color: var(--muted-text);
    font-size: 0.88em;
    font-weight: 650;
}

.profile-illustration {
    display: grid;
    grid-template-columns: minmax(220px, 0.8fr) minmax(220px, 1.2fr);
    gap: 22px;
    align-items: center;
    margin: 4px 0 28px;
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 20px;
    background: #1c1f20;
}

.profile-svg-wrap {
    display: flex;
    min-height: 190px;
    align-items: center;
    justify-content: center;
    border: 1px solid rgba(85, 183, 193, 0.2);
    border-radius: 12px;
    padding: 10px;
    background:
        linear-gradient(rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        #181a1b;
    background-size: 20px 20px;
}

.profile-svg {
    display: block;
    width: 100%;
    max-width: 320px;
    height: auto;
}

.profile-shape[hidden] {
    display: none;
}

.profile-solid {
    fill: rgba(85, 183, 193, 0.34);
    stroke: var(--primary);
    stroke-width: 3;
    vector-effect: non-scaling-stroke;
}

.profile-cutout {
    fill: #181a1b;
    stroke: var(--primary);
    stroke-width: 2.5;
    vector-effect: non-scaling-stroke;
}

.profile-dimension {
    stroke: #d9f4f6;
    stroke-width: 1.5;
    stroke-dasharray: 5 4;
    vector-effect: non-scaling-stroke;
}

.profile-label {
    fill: #d9f4f6;
    font-size: 10px;
    font-weight: 750;
    text-anchor: middle;
}

.profile-illustration figcaption {
    color: var(--muted-text);
}

.profile-illustration figcaption strong,
.profile-illustration figcaption span {
    display: block;
}

.profile-illustration figcaption strong {
    margin: 4px 0 8px;
    color: var(--text);
    font-size: 1.2rem;
}

.profile-illustration figcaption span {
    font-size: 0.9rem;
}

.beam-illustration {
    display: grid;
    grid-template-columns: minmax(320px, 1.35fr) minmax(190px, 0.65fr);
    gap: 22px;
    align-items: center;
    margin: 4px 0 28px;
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 20px;
    background: #1c1f20;
}

.beam-svg-wrap {
    display: flex;
    min-height: 220px;
    align-items: center;
    justify-content: center;
    border: 1px solid rgba(85, 183, 193, 0.2);
    border-radius: 12px;
    padding: 8px;
    background:
        linear-gradient(rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        #181a1b;
    background-size: 20px 20px;
}

.beam-svg {
    display: block;
    width: 100%;
    height: auto;
}

.beam-case[hidden] {
    display: none;
}

.beam-member {
    stroke: var(--primary);
    stroke-width: 7;
    stroke-linecap: round;
    vector-effect: non-scaling-stroke;
}

.beam-support {
    fill: rgba(85, 183, 193, 0.22);
    stroke: #d9f4f6;
    stroke-width: 2;
    vector-effect: non-scaling-stroke;
}

.beam-support-wheel {
    fill: #181a1b;
    stroke: #d9f4f6;
    stroke-width: 2;
    vector-effect: non-scaling-stroke;
}

.beam-ground,
.beam-fixed-wall,
.beam-wall-hatching line {
    stroke: #9da8a9;
    stroke-width: 2;
    vector-effect: non-scaling-stroke;
}

.beam-fixed-wall {
    stroke-width: 5;
}

.beam-load {
    stroke: #ffad66;
    stroke-width: 2.5;
    marker-end: url(#beam-arrowhead);
    vector-effect: non-scaling-stroke;
}

.beam-arrowhead {
    fill: #ffad66;
}

.beam-load-distribution {
    stroke: #ffad66;
    stroke-width: 2;
    vector-effect: non-scaling-stroke;
}

.beam-deflected {
    fill: none;
    stroke: rgba(139, 211, 218, 0.72);
    stroke-width: 2.5;
    stroke-dasharray: 7 5;
    vector-effect: non-scaling-stroke;
}

.beam-label {
    fill: #ffd0a8;
    font-size: 15px;
    font-weight: 800;
    text-anchor: middle;
}

.beam-illustration figcaption {
    color: var(--muted-text);
}

.beam-illustration figcaption strong,
.beam-illustration figcaption span {
    display: block;
}

.beam-illustration figcaption strong {
    margin: 4px 0 8px;
    color: var(--text);
    font-size: 1.15rem;
}

.beam-illustration figcaption span {
    font-size: 0.9rem;
}

.beam-result .result-metrics strong {
    font-size: 0.98rem;
}

.beam-formula-table {
    min-width: 680px;
}

.reynolds-illustration {
    display: grid;
    grid-template-columns: minmax(320px, 1.35fr) minmax(190px, 0.65fr);
    gap: 22px;
    align-items: center;
    margin: 4px 0 28px;
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 20px;
    background: #1c1f20;
}

.reynolds-svg-wrap {
    display: flex;
    min-height: 220px;
    align-items: center;
    justify-content: center;
    border: 1px solid rgba(85, 183, 193, 0.2);
    border-radius: 12px;
    padding: 8px;
    background:
        linear-gradient(rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(85, 183, 193, 0.04) 1px, transparent 1px),
        #181a1b;
    background-size: 20px 20px;
}

.reynolds-svg {
    display: block;
    width: 100%;
    height: auto;
}

.flow-pipe,
.flow-pipe-end {
    fill: none;
    stroke: #9da8a9;
    stroke-width: 3;
    vector-effect: non-scaling-stroke;
}

.flow-streamline {
    fill: none;
    stroke: rgba(139, 211, 218, 0.72);
    stroke-width: 2;
    marker-end: url(#flow-arrowhead);
    vector-effect: non-scaling-stroke;
}

.flow-streamline-main {
    stroke: var(--primary);
    stroke-width: 3;
}

.flow-arrowhead {
    fill: var(--primary);
}

.flow-dimension {
    stroke: #ffd0a8;
    stroke-width: 1.8;
    marker-start: url(#dimension-arrow-start);
    marker-end: url(#dimension-arrow-end);
    vector-effect: non-scaling-stroke;
}

.flow-dimension-arrow {
    fill: #ffd0a8;
}

.flow-svg-label {
    fill: #ffd0a8;
    font-size: 15px;
    font-weight: 800;
    text-anchor: middle;
}

.flow-input-symbol {
    fill: #d9f4f6;
}

.reynolds-illustration figcaption {
    color: var(--muted-text);
}

.reynolds-illustration figcaption strong,
.reynolds-illustration figcaption span {
    display: block;
}

.reynolds-illustration figcaption strong {
    margin: 4px 0 8px;
    color: var(--text);
    font-size: 1.15rem;
}

.reynolds-illustration figcaption span {
    font-size: 0.9rem;
}

.reynolds-result .result-feature {
    position: relative;
}

.flow-regime {
    display: inline-flex;
    width: fit-content;
    margin-top: 10px;
    border: 1px solid currentColor;
    border-radius: 999px;
    padding: 5px 10px;
    font-size: 0.78rem;
    font-weight: 850;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.flow-regime.laminar {
    background: rgba(85, 183, 193, 0.12);
    color: #8bd3da;
}

.flow-regime.transitional {
    background: rgba(255, 173, 102, 0.12);
    color: #ffb97a;
}

.flow-regime.turbulent {
    background: rgba(255, 123, 114, 0.12);
    color: #ff938c;
}

.regime-interpretation {
    margin: 16px 0 0;
    color: var(--muted-text);
}

.reynolds-regime-table .flow-regime {
    margin-top: 0;
    white-space: nowrap;
}

.material-result {
    margin-top: 24px;
    border: 1px solid rgba(85, 183, 193, 0.32);
    border-radius: var(--radius);
    padding: 22px;
    background: #1b2c2e;
}

.result-context {
    margin-bottom: 16px;
    color: var(--muted-text);
    font-size: 0.92rem;
    font-weight: 700;
}

.result-feature {
    border-bottom: 1px solid rgba(85, 183, 193, 0.22);
    padding-bottom: 18px;
}

.result-feature > span,
.result-metrics span {
    display: block;
    color: var(--muted-text);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.result-feature strong {
    display: block;
    margin-top: 2px;
    color: #f2f0ed;
    font-size: clamp(2rem, 6vw, 3.4rem);
    line-height: 1.1;
}

.result-feature small {
    color: var(--primary-dark);
    font-size: 0.48em;
}

.result-metrics {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    padding-top: 18px;
}

.result-metrics div {
    border: 1px solid rgba(85, 183, 193, 0.16);
    border-radius: 12px;
    padding: 14px;
    background: rgba(24, 26, 27, 0.45);
}

.result-metrics strong {
    display: block;
    margin-top: 5px;
    color: var(--text);
    overflow-wrap: anywhere;
}

.chip-list {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.category-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 8px 14px;
    background: #181a1b;
    color: var(--text);
    font: inherit;
    font-weight: 650;
    text-decoration: none;
    cursor: pointer;
    transition:
        background-color 0.2s ease,
        border-color 0.2s ease,
        color 0.2s ease,
        transform 0.2s ease;
}

.category-chip:hover {
    border-color: var(--primary);
    color: #e8e6e3;
    transform: translateY(-1px);
}

.category-chip.active {
    border-color: var(--primary);
    background: rgb(12, 61, 66);
    color: #e8e6e3;
}

.category-chip:focus-visible {
    outline: 3px solid rgba(19, 95, 104, 0.2);
    outline-offset: 2px;
}

.tool-group {
    margin-bottom: 56px;
}

.site-footer {
    padding: 44px 0;
    background: #111314;
    color: #f2f0ed;
}

.site-footer p {
    margin-bottom: 6px;
}

.site-footer .small {
    max-width: 700px;
    color: #aaa49b;
    font-size: 0.9rem;
}

.spaced-link {
    margin-right: 15px; /* Adds 15 pixels of space to the right */
  }

  .category-information {
      padding: 48px 0;
  }

  .category-info-summary {
      max-width: 720px;
      margin-bottom: 24px;
      color: var(--muted-text);
      font-size: 1.05rem;
  }

  .category-info-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 18px;
  }

  .category-info-card {
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 24px;
      background: var(--surface);
  }

  .category-info-card h3 {
      color: var(--text);
  }

  .category-info-card p,
  .category-info-card li {
      color: var(--muted-text);
  }

  .category-info-card p {
      margin-bottom: 0;
  }

  .category-info-card ul {
      margin: 0;
      padding-left: 22px;
  }

  .category-info-card li + li {
      margin-top: 6px;
  }

  .category-detail-sections {
      display: grid;
      gap: 18px;
      margin-top: 28px;
  }

  .category-detail-sections[hidden],
  .category-detail-card[hidden],
  .category-jump-links a[hidden] {
      display: none;
  }

  .category-jump-links {
      display: flex;
      flex-wrap: wrap;
      align-items: center;
      gap: 8px 14px;
      border-block: 1px solid var(--border);
      padding: 14px 0;
  }

  .category-jump-links span {
      color: var(--muted-text);
      font-weight: 750;
  }

  .category-jump-links a {
      font-weight: 700;
      text-underline-offset: 3px;
  }

  .category-detail-card {
      scroll-margin-top: 96px;
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 24px;
      background: var(--surface);
  }

  .category-detail-card > :last-child {
      margin-bottom: 0;
  }

  .category-detail-card p,
  .category-detail-card li,
  .category-detail-card td {
      color: var(--muted-text);
  }

  .category-detail-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 18px;
  }

  .formula-expression {
      display: inline-block;
      margin-bottom: 16px;
      border: 1px solid rgba(85, 183, 193, 0.35);
      border-radius: 12px;
      padding: 10px 16px;
      background: var(--accent);
      color: var(--primary-dark) !important;
      font-size: clamp(1.45rem, 4vw, 2rem);
      font-weight: 800;
      letter-spacing: 0.02em;
  }

  .technical-list,
  .worked-example-steps {
      margin: 0;
      padding-left: 22px;
  }

  .technical-list li + li,
  .worked-example-steps li + li {
      margin-top: 8px;
  }

  .conversion-table-wrap {
      overflow-x: auto;
      border: 1px solid var(--border);
      border-radius: 12px;
  }

  .conversion-table {
      width: 100%;
      border-collapse: collapse;
      min-width: 520px;
  }

  .conversion-table th,
  .conversion-table td {
      border-bottom: 1px solid var(--border);
      padding: 12px 14px;
      text-align: left;
      vertical-align: top;
  }

  .conversion-table thead th {
      background: var(--accent);
      color: var(--text);
  }

  .conversion-table tbody th {
      color: var(--text);
      font-weight: 700;
  }

  .conversion-table tbody tr:last-child th,
  .conversion-table tbody tr:last-child td {
      border-bottom: 0;
  }

  .worked-example-result {
      margin: 18px 0 10px;
      color: var(--primary-dark) !important;
      font-size: 1.25rem;
      font-weight: 800;
  }

  .detail-note {
      border-left: 3px solid var(--primary);
      padding-left: 14px;
      font-size: 0.95rem;
  }

  .faq-list {
      display: grid;
      gap: 10px;
  }

  .faq-list details {
      border: 1px solid var(--border);
      border-radius: 12px;
      background: #1c1f20;
  }

  .faq-list summary {
      padding: 14px 16px;
      color: var(--text);
      font-weight: 750;
      cursor: pointer;
  }

  .faq-list details[open] summary {
      border-bottom: 1px solid var(--border);
  }

  .faq-list p {
      margin: 0;
      padding: 14px 16px;
  }

  @media (max-width: 700px) {
      .category-info-grid,
      .category-detail-grid {
          grid-template-columns: 1fr;
      }

      .category-detail-card {
          padding: 20px;
      }

      .category-jump-links {
          align-items: flex-start;
          flex-direction: column;
      }
  }

@media (max-width: 850px) {
    .hero-grid,
    .two-column,
    .card-grid {
        grid-template-columns: 1fr;
    }

    .hero {
        padding: 68px 0;
    }

    .hero-panel {
        max-width: 560px;
    }
}

@media (max-width: 650px) {
    .nav-wrap {
        min-height: auto;
        align-items: flex-start;
        flex-direction: column;
        padding-block: 16px;
    }

    nav {
        width: 100%;
        gap: 14px;
        overflow-x: auto;
        white-space: nowrap;
    }

    .form-grid {
        grid-template-columns: 1fr;
    }

    .material-form-grid,
    .result-metrics {
        grid-template-columns: 1fr;
    }

    .profile-illustration {
        grid-template-columns: 1fr;
    }

    .beam-illustration {
        grid-template-columns: 1fr;
        padding: 16px;
    }

    .reynolds-illustration {
        grid-template-columns: 1fr;
        padding: 16px;
    }

    .profile-svg-wrap {
        min-height: 170px;
    }

    .beam-svg-wrap {
        min-height: 190px;
    }

    .reynolds-svg-wrap {
        min-height: 190px;
    }

    .swap-wrap {
        padding-bottom: 0;
    }

    .swap-button {
        transform: rotate(90deg);
    }
}