:root {
    --charcoal: #201D1A;
    --yellow: #F5B921;
    --steel: #57534C;
    --steel-light: #918C82;
    --paper: #EDEDE7;
    --paper-dim: #E2E1D9;
    --orange: #D65A1F;
    --moss: #445940;
    --line: #201D1A;
  }

  * { box-sizing: border-box; }

  html { scroll-behavior: smooth; }

  body {
    margin: 0;
    background: var(--paper);
    color: var(--charcoal);
    font-family: 'Work Sans', sans-serif;
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
  }

  h1, h2, h3, .num {
    font-family: 'Oswald', sans-serif;
    font-weight: 600;
    letter-spacing: 0.01em;
    margin: 0;
  }

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

  .wrap {
    max-width: 920px;
    margin: 0 auto;
    padding: 0 20px;
  }

  /* ---------- Header / band ---------- */
  .band {
    background: var(--charcoal);
    color: var(--paper);
    padding: 14px 0;
    border-bottom: 6px solid var(--yellow);
  }
  .band .wrap {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .brand {
    font-family: 'Oswald', sans-serif;
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: 0.02em;
  }
  .brand span { color: var(--yellow); }
  .band nav a {
    color: var(--paper);
    text-decoration: none;
    font-size: 0.92rem;
    margin-left: 22px;
    border-bottom: 1px solid transparent;
  }
  .band nav a:hover { border-bottom-color: var(--yellow); }
  @media (max-width: 560px) { .band nav { display: none; } }

  /* ---------- Hero / calculator ---------- */
  .hero {
    padding: 46px 0 20px;
  }
  .hero h1 {
    font-size: clamp(2rem, 5vw, 2.9rem);
    line-height: 1.05;
    max-width: 16ch;
  }
  .hero .sub {
    max-width: 52ch;
    color: var(--steel);
    margin-top: 14px;
    font-size: 1.05rem;
  }

  .docket {
    margin-top: 32px;
    background: #fff;
    border: 2px solid var(--charcoal);
    position: relative;
  }
  .docket::before {
    content: "";
    position: absolute;
    top: -2px; left: -2px; right: -2px;
    height: 8px;
    background: repeating-linear-gradient(
      -45deg,
      var(--yellow) 0 14px,
      var(--charcoal) 14px 28px
    );
  }
  .docket-inner { padding: 30px 24px 24px; margin-top: 8px; }

  .tabs {
    display: flex;
    border-bottom: 2px solid var(--charcoal);
    margin-bottom: 22px;
  }
  .tab-btn {
    font-family: 'Oswald', sans-serif;
    font-weight: 600;
    font-size: 0.95rem;
    background: none;
    border: none;
    padding: 10px 4px;
    margin-right: 26px;
    cursor: pointer;
    color: var(--steel-light);
    border-bottom: 3px solid transparent;
    transform: translateY(2px);
  }
  .tab-btn.active {
    color: var(--charcoal);
    border-bottom-color: var(--orange);
  }

  .field-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 16px;
  }
  @media (max-width: 620px) { .field-row { grid-template-columns: 1fr; } }

  label {
    display: block;
    font-size: 0.82rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--steel);
    margin-bottom: 6px;
  }
  select, input[type="number"] {
    width: 100%;
    padding: 11px 10px;
    border: 1.5px solid var(--charcoal);
    background: var(--paper);
    font-family: 'Work Sans', sans-serif;
    font-size: 1rem;
    color: var(--charcoal);
  }
  select:focus, input:focus {
    outline: 3px solid var(--orange);
    outline-offset: 1px;
  }

  .field { margin-bottom: 6px; }
  .pane { display: none; }
  .pane.active { display: block; }

  .calc-btn {
    margin-top: 20px;
    background: var(--charcoal);
    color: var(--paper);
    border: none;
    font-family: 'Oswald', sans-serif;
    font-weight: 600;
    font-size: 1rem;
    padding: 13px 26px;
    cursor: pointer;
    letter-spacing: 0.02em;
  }
  .calc-btn:hover { background: var(--orange); }

  .result {
    display: none;
    margin-top: 26px;
    border-top: 2px dashed var(--steel-light);
    padding-top: 22px;
  }
  .result.show { display: block; }
  .result-size {
    font-size: 2.1rem;
    color: var(--orange);
  }
  .result-meta {
    color: var(--steel);
    font-size: 0.95rem;
    margin-top: 4px;
  }
  .result-note {
    margin-top: 10px;
    font-size: 0.92rem;
    background: var(--paper-dim);
    padding: 10px 12px;
    border-left: 3px solid var(--moss);
  }

  /* ---------- Ad slot ---------- */
  .ad-slot {
    margin: 40px 0;
    padding: 14px;
    border: 1px dashed var(--steel-light);
    text-align: center;
    font-size: 0.75rem;
    color: var(--steel-light);
    text-transform: uppercase;
    letter-spacing: 0.08em;
  }

  /* ---------- Size guide ---------- */
  .guide { padding: 10px 0 40px; }
  .guide h2 {
    font-size: 1.7rem;
    margin-bottom: 6px;
  }
  .guide .sub { color: var(--steel); margin-bottom: 24px; }

  .size-row {
    display: grid;
    grid-template-columns: 46px 150px 1fr 130px;
    gap: 16px;
    align-items: baseline;
    padding: 16px 0;
    border-bottom: 1px solid var(--steel-light);
  }
  .size-row:first-of-type { border-top: 2px solid var(--charcoal); }
  @media (max-width: 680px) {
    .size-row { grid-template-columns: 30px 1fr; grid-template-areas: "n name" ". dims" ". use"; row-gap: 4px; }
    .size-row .num { grid-area: n; }
    .size-row .sname { grid-area: name; }
    .size-row .sdims { grid-area: dims; }
    .size-row .suse { grid-area: use; }
  }
  .num {
    color: var(--yellow);
    -webkit-text-stroke: 1px var(--charcoal);
    font-size: 1.5rem;
  }
  .sname { font-weight: 600; }
  .sdims { color: var(--steel); font-size: 0.92rem; }
  .suse { font-size: 0.92rem; }

  /* ---------- Info sections ---------- */
  .info { padding: 10px 0 50px; }
  .info h2 { font-size: 1.7rem; margin-bottom: 22px; }
  .qa { padding: 20px 0; border-bottom: 1px solid var(--steel-light); }
  .qa:first-of-type { border-top: 2px solid var(--charcoal); }
  .qa h3 { font-size: 1.1rem; margin-bottom: 8px; }
  .qa p { margin: 0; color: var(--steel); max-width: 68ch; }

  .cta-block {
    background: var(--charcoal);
    color: var(--paper);
    padding: 38px 0;
    margin-top: 10px;
  }
  .cta-block .wrap { text-align: left; }
  .cta-block h2 { color: var(--paper); font-size: 1.6rem; max-width: 24ch; }
  .cta-block p { color: var(--steel-light); margin-top: 10px; max-width: 50ch; }
  .cta-btn {
    display: inline-block;
    margin-top: 18px;
    background: var(--yellow);
    color: var(--charcoal);
    text-decoration: none;
    font-family: 'Oswald', sans-serif;
    font-weight: 600;
    padding: 12px 24px;
  }
  .cta-btn:hover { background: var(--orange); color: var(--paper); }

  footer {
    padding: 26px 0 40px;
    font-size: 0.82rem;
    color: var(--steel);
  }
  footer p { max-width: 70ch; }