:root {
  --bg: #ffffff;
  --text: #111111;
  --muted: #4a4a4a;
  --line: #d0d0d0;
  --panel: #f5f5f5;
  --primary: #003087;
  --primary-hover: #00276d;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
}

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

a:focus-visible,
button:focus-visible,
input:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.container {
  width: min(1100px, 92%);
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: #fff;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.9rem 0;
}

.logo {
  font-size: 1.1rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text);
}

.header-nav,
.footer-nav {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1rem;
}

.header-nav a,
.footer-nav a {
  text-decoration: none;
  color: var(--text);
}

.hero {
  padding: 2rem 0 1.1rem;
}

.hero h1 {
  margin: 0;
  font-size: clamp(1.8rem, 3.2vw, 2.3rem);
  line-height: 1.2;
}

.hero-subtitle {
  margin: 0.6rem 0 0;
  color: var(--muted);
}

.calculator-wrap {
  margin-bottom: 1.5rem;
}

.calculator-panel {
  border: 1px solid var(--line);
  background: var(--panel);
  padding: 1rem;
}

.rate-fieldset {
  margin: 0 0 1rem;
  padding: 0.75rem;
  border: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
}

.rate-fieldset legend {
  padding: 0 0.4rem;
  font-weight: 700;
}

.rate-fieldset label {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.98rem;
}

.inputs-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1rem;
  align-items: end;
}

.field-block label {
  display: block;
  font-weight: 700;
  margin-bottom: 0.35rem;
}

.input-shell {
  display: grid;
  grid-template-columns: auto 1fr;
  border: 1px solid var(--line);
  background: #fff;
}

.currency {
  padding: 0.62rem 0.7rem;
  border-right: 1px solid var(--line);
  color: #333;
}

.input-shell input {
  border: 0;
  min-width: 0;
  width: 100%;
  padding: 0.62rem 0.65rem;
  font-size: 1rem;
  color: var(--text);
  background: #fff;
}

.copy-btn,
.convert-btn {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--text);
  padding: 0.55rem 0.8rem;
  font-size: 0.95rem;
  cursor: pointer;
}

.copy-btn {
  margin-top: 0.45rem;
}

.convert-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
}

.convert-btn {
  font-size: 1.2rem;
  line-height: 1;
  min-width: 3rem;
}

.convert-label {
  font-size: 0.9rem;
  color: var(--muted);
}

.result-row {
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--line);
}

.result-label {
  margin: 0;
  font-weight: 700;
}

.result-value {
  margin: 0.2rem 0 0;
  font-size: clamp(1.55rem, 3vw, 2rem);
  font-weight: 700;
}

.primary-btn {
  margin-top: 1rem;
  width: 100%;
  border: 1px solid #002a72;
  background: var(--primary);
  color: #fff;
  font-size: 1.12rem;
  font-weight: 700;
  padding: 0.85rem 1rem;
  cursor: pointer;
}

.primary-btn:hover,
.primary-btn:focus-visible {
  background: var(--primary-hover);
}

.notice {
  border: 1px solid var(--line);
  padding: 1rem;
  background: #fff;
  margin-bottom: 2rem;
}

.notice h2 {
  margin: 0 0 0.55rem;
  font-size: 1.2rem;
}

.notice p {
  margin: 0 0 0.65rem;
}

.content-section {
  margin-bottom: 2rem;
}

.content-section h2 {
  margin: 0 0 0.6rem;
  font-size: 1.45rem;
}

.content-section h3 {
  margin: 1.15rem 0 0.45rem;
  font-size: 1.15rem;
}

.table-wrap {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
}

th,
td {
  border: 1px solid var(--line);
  padding: 0.65rem;
  text-align: left;
  vertical-align: top;
}

th {
  background: #efefef;
}

details {
  border: 1px solid var(--line);
  background: #fff;
  padding: 0.65rem;
  margin-bottom: 0.65rem;
}

summary {
  cursor: pointer;
  font-weight: 700;
}

summary::-webkit-details-marker {
  margin-right: 0.45rem;
}

.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 2.2rem;
  padding: 1rem 0;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-inner p {
  margin: 0;
  color: var(--muted);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 800px) {
  .inputs-row {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .convert-block {
    flex-direction: row;
    justify-content: flex-start;
  }

  .header-inner,
  .header-nav,
  .footer-nav {
    flex-wrap: wrap;
  }
}