*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #f4f6f9;
  --card-bg: #ffffff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --border: #e2e8f0;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07), 0 2px 4px rgba(0, 0, 0, 0.06);
  --radius: 12px;
  --radius-sm: 8px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  padding: 2rem 1rem;
}

.container {
  max-width: 860px;
  margin: 0 auto;
}

h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.75rem;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  margin-bottom: 1rem;
}

.card h2 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text);
}

.input-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}

.input-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.input-wrapper {
  display: flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.input-wrapper:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.12);
}

.input-wrapper input {
  flex: 1;
  border: none;
  outline: none;
  padding: 0.55rem 0.75rem;
  font-size: 0.95rem;
  font-family: inherit;
  background: transparent;
  color: var(--text);
}

.input-prefix,
.input-suffix {
  padding: 0 0.75rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  background: var(--bg);
  user-select: none;
  white-space: nowrap;
}

.input-prefix {
  border-right: 1px solid var(--border);
}

.input-suffix {
  border-left: 1px solid var(--border);
}

.btn-calculate {
  display: block;
  width: 100%;
  padding: 0.8rem;
  background: var(--primary);
  color: #fff;
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  box-shadow: var(--shadow-md);
  transition: background 0.15s, transform 0.1s;
  margin-bottom: 1.5rem;
}

.btn-calculate:hover {
  background: var(--primary-hover);
}

.btn-calculate:active {
  transform: scale(0.99);
}

.results {
  margin-top: 0.5rem;
}

.results.hidden {
  display: none;
}

.chart-container {
  position: relative;
  width: 100%;
  height: 380px;
}

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

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

thead th {
  background: var(--bg);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: var(--text-muted);
  padding: 0.6rem 0.5rem;
  text-align: right;
  white-space: nowrap;
  position: sticky;
  top: 0;
}

thead th:first-child {
  text-align: left;
}

tbody td {
  padding: 0.5rem;
  text-align: right;
  border-bottom: 1px solid var(--border);
  font-variant-numeric: tabular-nums;
}

tbody td:first-child {
  text-align: left;
  font-weight: 500;
}

tbody tr:hover {
  background: rgba(37, 99, 235, 0.03);
}

@media (max-width: 600px) {
  body {
    padding: 1rem 0.5rem;
  }

  .input-grid {
    grid-template-columns: 1fr;
  }

  .chart-container {
    height: 260px;
  }
}