:root {
  --border: rgba(0, 0, 0, 0.12);
  --soft: rgba(0, 191, 166, 0.06);
  --water: #0077BE;
  --water-hover: #005a8e;
  --water-light: rgba(0, 119, 190, 0.08);
  --water-border: rgba(0, 119, 190, 0.25);
}

body.dark-mode {
  --border: rgba(255, 255, 255, 0.12);
  --soft: rgba(0, 191, 166, 0.12);
  --water: #4da6cc;
  --water-hover: #3a8fb3;
  --water-light: rgba(77, 166, 204, 0.12);
  --water-border: rgba(77, 166, 204, 0.35);
}

.subhead {
  text-align: center;
  color: var(--text-sub);
  margin-bottom: 20px;
  font-weight: 600;
}

.controls-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 10px;
}

.control label {
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-main);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  display: block;
}

.segmented {
  display: flex;
  background: var(--bg);
  border: 2px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
}

.seg-btn {
  flex: 1;
  padding: 12px 12px;
  background: transparent;
  border: none;
  cursor: pointer;
  font-weight: 800;
  color: var(--text-main);
  transition: 0.2s;
}

.seg-btn.active {
  background: var(--water);
  color: white;
}

.select-input {
  width: 100%;
  padding: 12px 15px;
  border: 2px solid var(--border);
  border-radius: 12px;
  font-size: 1rem;
  font-family: 'Outfit', sans-serif;
  background: var(--bg);
  color: var(--text-main);
  font-weight: 700;
}

.input-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-top: 18px;
}

.input-group {
  display: flex;
  flex-direction: column;
}

.input-group label {
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-main);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.text-input {
  padding: 12px 15px;
  border: 2px solid var(--border);
  border-radius: 12px;
  font-size: 1.05rem;
  font-family: 'Outfit', sans-serif;
  background: var(--bg);
  color: var(--text-main);
  transition: 0.3s;
  font-weight: 700;
}

.text-input:focus {
  outline: none;
  border-color: var(--water);
  box-shadow: 0 0 0 3px rgba(0, 119, 190, 0.12);
}

.checkbox-group {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 8px;
}

.checkbox-group input[type="checkbox"] {
  width: 20px;
  height: 20px;
  accent-color: var(--water);
}

.checkbox-group label {
  font-weight: 700;
  color: var(--text-main);
  margin: 0;
  text-transform: none;
  letter-spacing: normal;
}

.calculate-btn {
  width: 100%;
  background: var(--water);
  color: white;
  border: none;
  padding: 16px;
  border-radius: 12px;
  font-size: 1.05rem;
  font-weight: 900;
  cursor: pointer;
  margin-top: 18px;
  transition: 0.3s;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.calculate-btn:hover {
  background: var(--water-hover);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 119, 190, 0.3);
}

.error-card {
  margin-top: 16px;
  border: 1px solid rgba(231, 76, 60, 0.35);
  background: rgba(231, 76, 60, 0.10);
  border-radius: 14px;
  padding: 14px;
  font-weight: 800;
  color: var(--text-main);
}

.results-section {
  margin-top: 28px;
  padding-top: 22px;
  border-top: 3px solid var(--water);
  text-align: left;
}

.results-section h3 {
  text-align: center;
  color: var(--water);
  font-size: 1.6rem;
  margin-bottom: 16px;
  font-weight: 900;
}

.big-number {
  background: var(--water-light);
  border: 2px solid var(--water);
  border-radius: 16px;
  padding: 18px;
  text-align: center;
  margin-bottom: 14px;
}

.big-label {
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-sub);
  margin-bottom: 6px;
}

.big-value {
  font-size: 2.6rem;
  font-weight: 900;
  color: var(--text-main);
}

.big-sub {
  font-weight: 800;
  color: var(--text-sub);
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  justify-content: center;
  margin: 14px 0;
}

.badge {
  display: inline-block;
  padding: 8px 12px;
  border-radius: 999px;
  font-weight: 900;
  border: 2px solid var(--water-border);
  background: var(--water-light);
  color: var(--text-main);
}

.note-card {
  margin-top: 14px;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 14px;
  background: rgba(0, 0, 0, 0.03);
  font-weight: 700;
  color: var(--text-main);
}

body.dark-mode .note-card {
  background: rgba(255, 255, 255, 0.06);
}

.warning-card {
  margin-top: 14px;
  border: 1px solid rgba(255, 193, 7, 0.35);
  background: rgba(255, 193, 7, 0.08);
  border-radius: 14px;
  padding: 14px;
}

.warning-card p {
  margin-top: 8px;
  color: var(--text-sub);
  font-weight: 700;
}

.tool-links {
  list-style: none;
  margin-left: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
}

.tool-link-btn {
  display: inline-block;
  background: var(--bg);
  border: 2px solid var(--border);
  color: var(--text-main);
  padding: 10px 14px;
  border-radius: 12px;
  text-decoration: none;
  font-weight: 900;
  transition: 0.2s;
}

.tool-link-btn:hover {
  border-color: var(--water);
  transform: translateY(-1px);
  box-shadow: 0 8px 18px rgba(0, 119, 190, 0.12);
}

@media (max-width: 900px) {
  .controls-grid,
  .input-grid {
    grid-template-columns: 1fr;
  }
}