:root {
  --bg: #f4f1ea;
  --text: #171717;
  --text-light: #f7f5ef;
  --muted: #6d6a63;
  --border: rgba(23, 23, 23, 0.08);
  --shadow: 0 12px 32px rgba(42, 38, 30, 0.06);
  --shadow-strong: 0 16px 44px rgba(0, 0, 0, 0.18);
  --radius: 22px;
  --radius-sm: 14px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  height: 100vh;
  overflow: hidden;
  font-family: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top, rgba(255, 255, 255, 0.7), transparent 32%),
    linear-gradient(180deg, #f7f3ec 0%, #efe8dc 100%);
}

button, select { font: inherit; }
a { color: inherit; text-decoration: none; }

.app {
  height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 14px 20px;
  max-width: 1120px;
  margin: 0 auto;
}

.header {
  flex-shrink: 0;
  margin-bottom: 12px;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.live-badge {
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(23, 23, 23, 0.06);
  font-size: 0.78rem;
  color: var(--muted);
}

/* ── Left + Right Layout ── */
.layout {
  flex: 1;
  display: flex;
  gap: 16px;
  min-height: 0;
}

/* ── Main Calculator ── */
.main-card {
  flex: 0 0 290px;
  display: flex;
  flex-direction: column;
  padding: 16px;
  border-radius: var(--radius);
  background: linear-gradient(180deg, #313131 0%, #1d1d1d 100%);
  color: var(--text-light);
  border: 1px solid rgba(255, 255, 255, 0.06);
  box-shadow: var(--shadow-strong);
}

.card-head {
  margin-bottom: 10px;
}

.card-head select {
  width: 100%;
  min-height: 32px;
  padding: 4px 8px;
  border: 0;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.08);
  color: var(--text-light);
  font-size: 0.82rem;
  outline: none;
  cursor: pointer;
}

.display-panel {
  padding: 14px 16px;
  border-radius: 16px;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.09), rgba(255, 255, 255, 0.04));
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.display-caption {
  margin: 0;
  font-size: 0.78rem;
  color: rgba(247, 245, 239, 0.55);
  letter-spacing: 0.04em;
  min-height: 1.2em;
  word-break: break-all;
}

.display-main {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
  margin-top: 8px;
}

.display-main strong {
  font-size: 1.6rem;
  letter-spacing: -0.04em;
  word-break: break-all;
}

.display-main span {
  font-size: 0.82rem;
  color: rgba(247, 245, 239, 0.6);
}

.keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 7px;
  margin-top: 12px;
}

.key {
  min-height: 40px;
  border: 0;
  border-radius: var(--radius-sm);
  background: #f2ede3;
  color: #1f1f1f;
  font-size: 0.92rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.15s ease;
}

.key:hover { transform: translateY(-1px); }
.key-soft { background: #d8d0c1; }
.key-accent { background: #cabba0; }
.key-wide { grid-column: span 2; }
.key-equals {
  grid-row: span 2;
  min-height: 87px;
}

/* ── Right Cards Panel ── */
.rates-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 7px;
  overflow-y: auto;
  padding-right: 2px;
}

.rate-card {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.75), rgba(255, 255, 255, 0.56));
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform 0.15s ease, border-color 0.15s ease;
  min-height: 52px;
}

.rate-card:hover { transform: translateY(-1px); }
.rate-card.active {
  border-color: rgba(23, 23, 23, 0.18);
}

.rate-card-flag {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--bg);
  font-size: 0.82rem;
}

.rate-card-info {
  flex: 0 0 50px;
}

.rate-card-name {
  margin: 0;
  font-size: 0.82rem;
  font-weight: 600;
  line-height: 1.2;
}

.rate-card-code {
  margin: 1px 0 0;
  font-size: 0.68rem;
  color: var(--muted);
}

.rate-card-formula {
  flex: 1;
  min-width: 0;
  text-align: right;
  font-size: 0.72rem;
  color: var(--muted);
  line-height: 1.3;
}

.rate-card-formula .result {
  display: block;
  font-weight: 600;
  font-size: 1rem;
  color: var(--text);
  margin-top: 1px;
}

/* ── Responsive ── */
@media (max-width: 720px) {
  body { overflow: auto; }
  .app { height: auto; }
  .layout {
    flex-direction: column;
  }
  .main-card {
    flex: none;
    width: 100%;
  }
  .rates-panel {
    flex-direction: row;
    overflow-x: auto;
    gap: 8px;
    padding-bottom: 8px;
  }
  .rate-card {
    flex: 0 0 160px;
    flex-direction: column;
    align-items: flex-start;
    min-height: auto;
  }
  .rate-card-formula {
    text-align: left;
  }
}