:root {
        --bg: #f7f6f2;
        --surface: #ffffff;
        --surface-2: #efeee8;
        --ink: #1c2420;
        --ink-soft: #4a554e;
        --line: #d9d7cd;
        --accent: #166534;
        --accent-strong: #14532d;
        --accent-soft: #e3efe4;
        --gold: #b45309;
        --gold-soft: #faf0dd;
        --danger: #b3261e;
        --radius: 10px;
        --shadow: 0 1px 2px rgba(28,36,32,.06), 0 4px 14px rgba(28,36,32,.05);
      }
      @media (prefers-color-scheme: dark) {
        :root {
          --bg: #141816;
          --surface: #1e2421;
          --surface-2: #262d29;
          --ink: #eef1ee;
          --ink-soft: #a9b4ac;
          --line: #39423c;
          --accent: #4ade80;
          --accent-strong: #86efac;
          --accent-soft: #1d2f23;
          --gold: #f0b35e;
          --gold-soft: #33291a;
          --danger: #f28b82;
          --shadow: 0 1px 2px rgba(0,0,0,.4), 0 4px 14px rgba(0,0,0,.3);
        }
      }
      * { box-sizing: border-box; }
      html { -webkit-text-size-adjust: 100%; }
      body {
        margin: 0;
        background: var(--bg);
        color: var(--ink);
        font-family: "IBM Plex Sans", -apple-system, "Segoe UI", Roboto, sans-serif;
        font-size: 16px;
        line-height: 1.55;
      }
      button, [role="button"], select, summary, input:not([type="checkbox"], [type="radio"]) { min-height: 2.25rem; }
      a { color: var(--accent); }
      a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible {
        outline: 2px solid var(--accent);
        outline-offset: 2px;
      }
      .wrap { max-width: 880px; margin: 0 auto; padding: 0 18px; }

      /* ---------- Header / nav ---------- */
      header.site {
        background: var(--surface);
        border-bottom: 1px solid var(--line);
        position: sticky; top: 0; z-index: 20;
      }
      .site-bar {
        display: flex; align-items: center; gap: 14px;
        padding-top: 12px; padding-bottom: 12px;
      }
      .brand {
        font-weight: 700; font-size: 1.15rem; letter-spacing: -.01em;
        color: var(--ink); text-decoration: none; white-space: nowrap;
        display: flex; align-items: center; gap: 9px;
      }
      .brand .mark {
        display: inline-flex; align-items: center; justify-content: center;
        width: 30px; height: 30px; border-radius: 8px;
        background: var(--accent); color: #fff;
        font-family: "IBM Plex Mono", monospace; font-weight: 600; font-size: 1rem;
      }
      @media (prefers-color-scheme: dark) { .brand .mark { color: #0e2416; } }
      nav.main { margin-left: auto; }
      nav.main ul {
        list-style: none; margin: 0; padding: 0;
        display: flex; gap: 2px; flex-wrap: wrap; justify-content: flex-end;
      }
      nav.main a {
        display: inline-flex; align-items: center; min-height: 36px;
        padding: 4px 10px; border-radius: 8px;
        color: var(--ink-soft); text-decoration: none; font-size: .92rem; font-weight: 500;
      }
      nav.main a:hover { background: var(--surface-2); color: var(--ink); }
      nav.main a[aria-current="page"] { background: var(--accent-soft); color: var(--accent-strong); }
      @media (max-width: 640px) {
        .site-bar { flex-direction: column; align-items: flex-start; gap: 6px; }
        nav.main { margin-left: 0; }
        nav.main ul { justify-content: flex-start; }
      }

      /* ---------- Currency bar ---------- */
      .currency-bar {
        border-top: 1px solid var(--line);
        background: var(--surface-2);
      }
      .currency-inner {
        display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
        padding-top: 8px; padding-bottom: 8px;
      }
      .currency-inner label { margin: 0; font-size: .88rem; }
      .currency-inner select {
        width: auto; min-width: 190px; padding: 6px 10px; font-size: .95rem;
      }
      .rate-info { color: var(--ink-soft); font-size: .82rem; }
      .rate-info .live-dot { color: var(--accent); font-weight: 700; }
      @media (max-width: 640px) {
        .currency-inner select { flex: 1; min-width: 150px; }
        .rate-info { width: 100%; }
      }

      /* Quick-pick buttons (tip %) */
      .quick-row { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 10px; }
      .quick-row button {
        min-height: 40px; padding: 6px 14px; cursor: pointer;
        background: var(--surface-2); color: var(--ink-soft);
        border: 1px solid var(--line); border-radius: 8px;
        font: inherit; font-weight: 600; font-size: .92rem;
      }
      .quick-row button[aria-pressed="true"] {
        background: var(--accent); border-color: var(--accent); color: #fff;
      }
      @media (prefers-color-scheme: dark) { .quick-row button[aria-pressed="true"] { color: #0e2416; } }
      td.num.neg { color: var(--danger); }
      .mode-group { display: none; }
      .mode-group.active { display: block; }

      /* ---------- Views ---------- */
      .view { display: none; padding: 34px 0 56px; }
      .view.active { display: block; }
      h1 { font-size: 1.9rem; line-height: 1.2; margin: 0 0 10px; letter-spacing: -.02em; }
      h2 { font-size: 1.25rem; margin: 34px 0 10px; letter-spacing: -.01em; }
      h3 { font-size: 1.02rem; margin: 22px 0 6px; }
      p { margin: 0 0 12px; }
      .lede { font-size: 1.06rem; color: var(--ink-soft); max-width: 62ch; }
      .crumbs { font-size: .85rem; color: var(--ink-soft); margin-bottom: 14px; }
      .crumbs a { color: var(--ink-soft); }

      /* ---------- Home tool grid ---------- */
      .tool-grid {
        display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 26px;
      }
      @media (max-width: 620px) { .tool-grid { grid-template-columns: 1fr; } }
      .tool-card {
        display: block; text-decoration: none; color: var(--ink);
        background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
        padding: 20px; box-shadow: var(--shadow);
      }
      .tool-card:hover { border-color: var(--accent); }
      .tool-card .t-icon {
        font-family: "IBM Plex Mono", monospace; font-weight: 600;
        display: inline-flex; align-items: center; justify-content: center;
        width: 38px; height: 38px; border-radius: 9px;
        background: var(--accent-soft); color: var(--accent-strong);
        font-size: .95rem; margin-bottom: 12px;
      }
      .tool-card h2 { margin: 0 0 6px; font-size: 1.12rem; }
      .tool-card p { margin: 0; color: var(--ink-soft); font-size: .94rem; }
      .tool-card .go { display: inline-block; margin-top: 12px; font-weight: 600; color: var(--accent); font-size: .92rem; }

      .note-band {
        margin-top: 30px; background: var(--gold-soft); border: 1px solid var(--line);
        border-radius: var(--radius); padding: 16px 18px; font-size: .95rem;
      }
      .note-band strong { color: var(--gold); }

      /* ---------- Calculator layout ---------- */
      .calc-grid {
        display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-top: 24px;
        align-items: start;
      }
      @media (max-width: 680px) { .calc-grid { grid-template-columns: 1fr; } }
      .panel {
        background: var(--surface); border: 1px solid var(--line);
        border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow);
      }
      .panel h2 { margin-top: 0; font-size: 1.05rem; }
      .field { margin-bottom: 16px; }
      .field:last-child { margin-bottom: 0; }
      label { display: block; font-weight: 600; font-size: .92rem; margin-bottom: 6px; }
      .hint { font-weight: 400; color: var(--ink-soft); font-size: .82rem; display: block; margin-top: 2px; }
      .input-row { display: flex; align-items: stretch; }
      .prefix, .suffix {
        display: inline-flex; align-items: center; padding: 0 10px;
        background: var(--surface-2); border: 1px solid var(--line);
        color: var(--ink-soft); font-family: "IBM Plex Mono", monospace; font-size: .95rem;
      }
      .prefix { border-right: 0; border-radius: 8px 0 0 8px; }
      .suffix { border-left: 0; border-radius: 0 8px 8px 0; }
      input[type="number"], input[type="text"], input[type="email"], textarea, select {
        width: 100%; padding: 9px 12px; font-size: 1rem; color: var(--ink);
        background: var(--surface); border: 1px solid var(--line); border-radius: 8px;
        font-family: inherit;
      }
      .input-row input { border-radius: 0; }
      .input-row input:first-child { border-radius: 8px 0 0 8px; }
      .input-row input:last-child { border-radius: 0 8px 8px 0; }
      .input-row .prefix + input { border-radius: 0 8px 8px 0; }
      .input-row .prefix + input:not(:last-child) { border-radius: 0; }
      select { appearance: auto; }
      .seg { display: flex; gap: 8px; }
      .seg button {
        flex: 1; min-height: 44px; padding: 8px 10px; cursor: pointer;
        background: var(--surface-2); color: var(--ink-soft);
        border: 1px solid var(--line); border-radius: 8px;
        font: inherit; font-weight: 600; font-size: .95rem;
      }
      .seg button[aria-pressed="true"] {
        background: var(--accent); border-color: var(--accent); color: #fff;
      }
      @media (prefers-color-scheme: dark) { .seg button[aria-pressed="true"] { color: #0e2416; } }

      /* Results */
      .result-hero { margin-bottom: 16px; }
      .result-hero .r-label { font-size: .85rem; font-weight: 600; color: var(--ink-soft); text-transform: uppercase; letter-spacing: .06em; }
      .result-hero .r-value {
        font-family: "IBM Plex Mono", monospace; font-weight: 600;
        font-size: 2.1rem; line-height: 1.15; color: var(--accent-strong);
      }
      .result-hero .r-sub { color: var(--ink-soft); font-size: .92rem; }
      table.breakdown { width: 100%; border-collapse: collapse; font-size: .95rem; }
      table.breakdown th, table.breakdown td {
        padding: 8px 4px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top;
      }
      table.breakdown td.num, table.breakdown th.num {
        text-align: right; font-family: "IBM Plex Mono", monospace; white-space: nowrap;
      }
      table.breakdown tr.total td { border-bottom: 0; border-top: 2px solid var(--ink); font-weight: 700; }
      table.breakdown .calc-note { color: var(--ink-soft); font-size: .82rem; display: block; }
      .equiv-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 4px; }
      .equiv {
        background: var(--surface-2); border-radius: 8px; padding: 10px 12px;
      }
      .equiv .e-label { font-size: .8rem; font-weight: 600; color: var(--ink-soft); text-transform: uppercase; letter-spacing: .05em; }
      .equiv .e-value { font-family: "IBM Plex Mono", monospace; font-weight: 600; font-size: 1.12rem; }
      .gross-note {
        margin-top: 14px; font-size: .9rem; background: var(--gold-soft);
        border-radius: 8px; padding: 10px 12px;
      }

      /* ---------- Content prose ---------- */
      .prose { max-width: 68ch; }
      .prose ul { margin: 0 0 12px; padding-left: 22px; }
      .prose li { margin-bottom: 6px; }
      .formula {
        font-family: "IBM Plex Mono", monospace; font-size: .95rem;
        background: var(--surface-2); border: 1px solid var(--line); border-radius: 8px;
        padding: 12px 14px; margin: 10px 0 14px; white-space: normal; overflow-wrap: anywhere;
      }
      .example {
        background: var(--accent-soft); border-radius: var(--radius);
        padding: 16px 18px; margin: 12px 0;
      }
      .example h3 { margin-top: 0; }
      .example p:last-child { margin-bottom: 0; }
      code { font-family: "IBM Plex Mono", monospace; font-size: .92em; }

      /* ---------- Contact ---------- */
      .btn {
        display: inline-flex; align-items: center; justify-content: center;
        min-height: 46px; padding: 10px 20px; border: 0; border-radius: 8px;
        background: var(--accent); color: #fff; font: inherit; font-weight: 600;
        cursor: pointer; text-decoration: none;
      }
      @media (prefers-color-scheme: dark) { .btn { color: #0e2416; } }
      .btn:hover { background: var(--accent-strong); }
      textarea { min-height: 130px; resize: vertical; }

      /* ---------- Footer ---------- */
      footer.site {
        border-top: 1px solid var(--line); background: var(--surface);
        margin-top: 20px;
      }
      .foot {
        padding-top: 22px; padding-bottom: 30px;
        display: flex; flex-wrap: wrap; gap: 10px 26px; align-items: baseline;
      }
      .foot nav ul { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 4px 16px; }
      .foot nav a { color: var(--ink-soft); text-decoration: none; font-size: .9rem; display: inline-flex; align-items: center; min-height: 32px; }
      .foot nav a:hover { color: var(--ink); text-decoration: underline; }
      .foot .fine { width: 100%; color: var(--ink-soft); font-size: .82rem; margin-top: 6px; }