.tool-ui {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Mode Navigation Bar */
.calc-nav {
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  padding-bottom: 0.25rem;
  scrollbar-width: none;
}

.calc-nav::-webkit-scrollbar {
  display: none;
}

.calc-nav-tab {
  background: #1A1D27;
  border: 1px solid #2A2D3A;
  color: #6B7280;
  padding: 0.55rem 1rem;
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.calc-nav-tab.active {
  background: #4F8EF7;
  border-color: #4F8EF7;
  color: #FFFFFF;
}

.calc-nav-tab:hover:not(.active) {
  border-color: #4F8EF7;
  color: #F0F2F8;
}

/* Calculator Card */
.calc-card {
  background: #1A1D27;
  border: 1px solid #2A2D3A;
  border-radius: 12px;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.card-title {
  font-family: 'DM Sans', sans-serif;
  font-size: 1.15rem;
  font-weight: 600;
  color: #F0F2F8;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card-desc {
  font-size: 0.85rem;
  color: #6B7280;
}

/* Inputs Row */
.inputs-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.input-box {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  flex: 1;
  min-width: 140px;
}

.input-label {
  font-size: 0.8rem;
  color: #6B7280;
  font-weight: 500;
}

.calc-input {
  background: #0F1117;
  border: 1px solid #2A2D3A;
  border-radius: 8px;
  padding: 0.65rem 0.85rem;
  color: #F0F2F8;
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.05rem;
  outline: none;
  width: 100%;
  transition: border-color 0.2s;
}

.calc-input:focus {
  border-color: #4F8EF7;
}

.math-symbol {
  font-size: 1.2rem;
  font-weight: 600;
  color: #6B7280;
  align-self: flex-end;
  margin-bottom: 0.75rem;
}

/* Quick Presets */
.preset-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.preset-chip {
  background: #0F1117;
  border: 1px solid #2A2D3A;
  color: #6B7280;
  padding: 0.3rem 0.6rem;
  border-radius: 6px;
  font-size: 0.775rem;
  font-family: 'JetBrains Mono', monospace;
  cursor: pointer;
  transition: all 0.2s;
}

.preset-chip:hover {
  border-color: #4F8EF7;
  color: #F0F2F8;
}

/* Result Box */
.result-box {
  background: #0F1117;
  border: 1px solid #2A2D3A;
  border-radius: 10px;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: border-color 0.2s;
}

.result-box:hover {
  border-color: #4F8EF7;
}

.result-main {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.result-value-group {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.result-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: #6B7280;
  font-weight: 600;
}

.result-value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.75rem;
  font-weight: 700;
  color: #4ade80;
}

.result-value.negative {
  color: #f87171;
}

.formula-text {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.8rem;
  color: #6B7280;
  background: rgba(42, 45, 58, 0.4);
  padding: 0.5rem 0.75rem;
  border-radius: 6px;
  border-left: 3px solid #4F8EF7;
}

/* Visual Progress / Ratio Bar */
.progress-bar-bg {
  width: 100%;
  height: 8px;
  background: #1A1D27;
  border-radius: 4px;
  overflow: hidden;
  position: relative;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, #4F8EF7, #4ade80);
  border-radius: 4px;
  transition: width 0.3s ease;
  max-width: 100%;
}

/* Buttons */
.btn-copy {
  background: transparent;
  color: #F0F2F8;
  border: 1px solid #2A2D3A;
  border-radius: 8px;
  padding: 0.5rem 0.85rem;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.btn-copy:hover {
  border-color: #4F8EF7;
  color: #4F8EF7;
}

/* Secondary Stat Row (Tip, Discount breakdowns) */
.sub-stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 0.75rem;
  margin-top: 0.25rem;
}

.sub-stat-card {
  background: #141720;
  border: 1px solid #2A2D3A;
  border-radius: 8px;
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.sub-stat-label {
  font-size: 0.725rem;
  color: #6B7280;
  text-transform: uppercase;
}

.sub-stat-val {
  font-family: 'JetBrains Mono', monospace;
  font-size: 1.1rem;
  font-weight: 600;
  color: #F0F2F8;
}