:root {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: #0f172a;
  background-color: #f8fafc;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  background: #f5f6fa;
  padding: 1.5rem 1rem 3rem;
}

.hero {
  text-align: center;
  margin-bottom: 1rem;
}

.hero h1 {
  margin: 0;
  font-size: 2.4rem;
  letter-spacing: 0.05em;
}

.hero p {
  margin: 0.5rem 0 0;
  color: #475569;
}

.converter {
  width: min(720px, 100%);
  background: #fff;
  border-radius: 1.25rem;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  box-shadow: 0 20px 60px rgba(15, 23, 42, 0.08);
}

.quick-panel {
  border-radius: 1rem;
  padding: 1rem;
  background: #f8fafc;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.section-label {
  margin: 0 0 0.5rem;
  font-weight: 600;
  color: #0f172a;
}

.quick-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}

.quick-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 0.9rem;
  border-radius: 0.9rem;
  background: #fff;
  box-shadow: inset 0 0 0 1px #e2e8f0;
  justify-content: flex-end;
}

.quick-item span {
  font-weight: 600;
  color: #475569;
  flex: 1;
  text-align: right;
}

.quick-input-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.quick-item input {
  width: 6.4rem;
  padding: 0.55rem 0.7rem;
  border-radius: 0.6rem;
  border: 1px solid #d7dee8;
  font-size: 1.05rem;
  font-weight: 600;
  color: #0f172a;
  background: #fff;
  appearance: textfield;
}

.quick-item input:focus {
  outline: 2px solid #0ea5e9;
  border-color: transparent;
}

.quick-item input::-webkit-outer-spin-button,
.quick-item input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.copy-button {
  border: 1px solid #cbd5e1;
  background: #f8fafc;
  color: #0f172a;
  border-radius: 0.6rem;
  padding: 0.5rem;
  width: 2.5rem;
  height: 2.5rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.copy-button svg {
  width: 1.15rem;
  height: 1.15rem;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.copy-button:focus-visible {
  outline: 2px solid #0ea5e9;
  outline-offset: 1px;
}

.copy-button:hover {
  background: #eef6ff;
}

.quick-item.active {
  box-shadow: inset 0 0 0 1.5px #0ea5e9;
  background: #f0f9ff;
}

.quick-item[data-currency='JPY'].active {
  box-shadow: inset 0 0 0 1px #e2e8f0;
  background: #fff;
}

.quick-hint {
  margin: 0;
  font-size: 0.9rem;
  color: #64748b;
}

.copy-status {
  min-height: 1.2rem;
  margin: -0.15rem 0 0;
  font-size: 0.88rem;
  color: #0369a1;
}

.copy-status.is-error {
  color: #b91c1c;
}

.rate-info {
  margin: 0;
  font-size: 0.9rem;
  color: #475569;
}

.timestamp,
.disclaimer {
  margin: 0;
  font-size: 0.95rem;
  color: #475569;
}

.disclaimer {
  line-height: 1.4;
}

@media (max-width: 640px) {
  .quick-list {
    grid-template-columns: 1fr;
  }

  .quick-panel {
    padding: 0.9rem;
  }

  .quick-item {
    justify-content: space-between;
  }

  .quick-item input {
    width: 100%;
    min-width: 0;
  }

  .quick-input-row {
    flex: 1;
  }
}