/* Tabs */
.tab-bar {
  display: flex;
  gap: 4px;
  margin-bottom: 20px;
  border-bottom: 2px solid var(--color-border);
}

.tab-btn {
  background: none;
  border: none;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--color-text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: all 0.2s;
}

.tab-btn:hover {
  color: var(--color-text);
}

.tab-btn.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
  font-weight: 600;
}

.tab-panel {
  display: none;
}

.tab-panel.active {
  display: block;
}

/* Form */
.calc-form {
  max-width: 480px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 14px;
  color: var(--color-text);
  margin-bottom: 6px;
}

.form-input {
  width: 100%;
  padding: 12px 14px;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  font-size: 16px;
  color: var(--color-text);
  transition: border-color 0.2s;
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.input-row {
  display: flex;
  gap: 8px;
  align-items: center;
}

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

.today-btn {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  padding: 8px 12px;
  font-size: 12px;
  cursor: pointer;
  color: var(--color-text-muted);
  white-space: nowrap;
  transition: all 0.2s;
}

.today-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.calc-btn {
  background: var(--color-primary);
  color: white;
  border: none;
  padding: 14px;
  border-radius: 10px;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
  width: 100%;
  transition: background 0.2s, transform 0.1s;
}

.calc-btn:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
}

.calc-btn:active {
  transform: translateY(0);
}

/* Direction toggle */
.dir-toggle {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
}

.dir-toggle label {
  flex: 1;
  text-align: center;
  padding: 10px;
  border: 2px solid var(--color-border);
  border-radius: 8px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}

.dir-toggle input[type="radio"] {
  display: none;
}

.dir-toggle input[type="radio"]:checked + label {
  border-color: var(--color-primary);
  background: #eef2ff;
  color: var(--color-primary);
  font-weight: 600;
}

/* Results */
.calc-result {
  display: none;
  margin-top: 24px;
  max-width: 480px;
  margin-left: auto;
  margin-right: auto;
}

.result-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.result-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 16px;
  text-align: center;
}

.result-card .value {
  font-size: 22px;
  font-weight: 700;
  color: var(--color-primary);
  font-variant-numeric: tabular-nums;
}

.result-card .label {
  font-size: 12px;
  color: var(--color-text-muted);
  margin-top: 4px;
}

/* Add/Sub result */
.result-single {
  background: #eef2ff;
  border: 2px solid var(--color-primary);
  border-radius: 12px;
  padding: 20px;
  text-align: center;
}

.result-single .label {
  font-size: 14px;
  color: var(--color-text-muted);
  margin-bottom: 4px;
}

.result-single .value {
  font-size: 24px;
  font-weight: 700;
  color: var(--color-primary);
}

/* D-day */
.dday-result {
  text-align: center;
}

.dday-name {
  font-size: 16px;
  color: var(--color-text-muted);
  margin-bottom: 8px;
}

.dday-count {
  font-size: 56px;
  font-weight: 800;
  margin-bottom: 8px;
}

.dday-count.future { color: var(--color-primary); }
.dday-count.today { color: #16a34a; }
.dday-count.past { color: #dc2626; }

.dday-detail {
  font-size: 14px;
  color: var(--color-text-muted);
}

@media (max-width: 640px) {
  .tab-btn {
    padding: 8px 10px;
    font-size: 13px;
  }

  .dday-count {
    font-size: 44px;
  }
}