.sqft-calc {
  --calc-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  --calc-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --calc-bg: #f8f9fb;
  --calc-card: #ffffff;
  --calc-fg: #0f172a;
  --calc-muted: #64748b;
  --calc-border: #e2e8f0;
  --calc-primary: #2563eb;
  --calc-primary-light: #eff6ff;
  --calc-accent: #ea580c;
  --calc-secondary: #f1f5f9;
  --calc-radius: 0.75rem;
  --calc-result-bg: #0f172a;
  --calc-result-fg: #ffffff;

  font-family: var(--calc-font);
  color: var(--calc-fg);
  line-height: 1.6;
  max-width: 100%;
}

.sqft-calc *,
.sqft-calc *::before,
.sqft-calc *::after {
  box-sizing: border-box;
}

/* Mode Switcher */
.calc-mode-switcher {
  display: flex;
  padding: 4px;
  background: var(--calc-secondary);
  border-radius: 8px;
  width: fit-content;
  margin-bottom: 24px;
}
.calc-mode-btn {
  padding: 10px 20px;
  border: none;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 500;
  font-family: var(--calc-font);
  cursor: pointer;
  background: transparent;
  color: var(--calc-muted);
  transition: all 0.2s;
}
.calc-mode-btn.active {
  background: var(--calc-card);
  color: var(--calc-fg);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}
.calc-mode-btn:hover:not(.active) {
  color: var(--calc-fg);
}

/* Inputs */
.calc-inputs {
  background: var(--calc-card);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius);
  padding: 24px;
  margin-bottom: 16px;
}
.calc-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 20px;
}
.calc-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 4px;
}
.calc-label {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--calc-muted);
}
.calc-required {
  color: #ef4444;
}
.calc-input,
.calc-select {
  width: 100%;
  height: 48px;
  padding: 0 16px;
  background: var(--calc-secondary);
  border: 1px solid var(--calc-border);
  border-radius: 8px;
  font-family: var(--calc-mono);
  font-size: 16px;
  color: var(--calc-fg);
  transition: box-shadow 0.2s, border-color 0.2s;
  outline: none;
  -webkit-appearance: none;
}
.calc-input:focus,
.calc-select:focus {
  border-color: var(--calc-primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}

/* Slider */
.calc-slider-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.calc-slider-value {
  font-family: var(--calc-mono);
  font-size: 14px;
  font-weight: 500;
  color: var(--calc-fg);
}
.calc-range {
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: var(--calc-secondary);
  -webkit-appearance: none;
  appearance: none;
  outline: none;
  cursor: pointer;
  margin: 8px 0 4px;
}
.calc-range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--calc-primary);
  cursor: pointer;
  border: 2px solid var(--calc-card);
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
.calc-range::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--calc-primary);
  cursor: pointer;
  border: 2px solid var(--calc-card);
  box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}
.calc-range-labels {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  color: var(--calc-muted);
}

/* Material Grid */
.calc-material-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}
.calc-mat-btn {
  padding: 12px;
  border: 1px solid var(--calc-border);
  border-radius: 8px;
  background: var(--calc-card);
  cursor: pointer;
  text-align: left;
  transition: all 0.2s;
  font-family: var(--calc-font);
}
.calc-mat-btn:hover {
  border-color: rgba(37,99,235,0.4);
}
.calc-mat-btn.active {
  border-color: var(--calc-primary);
  background: rgba(37,99,235,0.04);
  box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}
.calc-mat-name {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--calc-fg);
}
.calc-mat-density {
  display: block;
  font-size: 10px;
  color: var(--calc-muted);
  margin-top: 2px;
}

/* Reset */
.calc-reset-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 0;
  margin-bottom: 24px;
  border: none;
  background: transparent;
  font-family: var(--calc-font);
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--calc-muted);
  cursor: pointer;
  transition: color 0.2s;
}
.calc-reset-btn:hover {
  color: var(--calc-accent);
}

/* Result Panel */
.calc-result-panel {
  background: var(--calc-result-bg);
  color: var(--calc-result-fg);
  border-radius: 20px;
  padding: 32px;
  margin-bottom: 24px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 8px 32px rgba(0,0,0,0.18);
}
.calc-result-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--calc-primary);
}
.calc-result-main {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-top: 16px;
}
.calc-result-number {
  font-family: var(--calc-mono);
  font-size: clamp(40px, 8vw, 64px);
  font-weight: 700;
  letter-spacing: -0.04em;
  color: var(--calc-accent);
  transition: all 0.3s;
  font-variant-numeric: tabular-nums;
}
.calc-result-unit {
  font-size: clamp(16px, 3vw, 22px);
  font-weight: 300;
  color: var(--calc-muted);
}
.calc-result-secondary {
  font-family: var(--calc-mono);
  font-size: 14px;
  color: var(--calc-muted);
  margin-top: 8px;
  line-height: 1.8;
}
.calc-result-divider {
  height: 1px;
  background: rgba(255,255,255,0.12);
  margin: 24px 0;
}
.calc-result-breakdown {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}
.calc-breakdown-row {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--calc-muted);
}
.calc-breakdown-row span:last-child {
  color: var(--calc-result-fg);
  font-family: var(--calc-mono);
}

/* Print Button */
.calc-print-btn {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 12px;
  background: var(--calc-primary);
  color: #fff;
  font-family: var(--calc-font);
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  transition: background 0.2s, opacity 0.2s, transform 0.1s;
}
.calc-print-btn:hover:not(:disabled) {
  background: #1d4ed8;
}
.calc-print-btn:active:not(:disabled) {
  transform: scale(0.98);
}
.calc-print-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

/* Formula Section */
.calc-formula {
  background: var(--calc-primary-light);
  border: 1px solid #dbeafe;
  border-radius: var(--calc-radius);
  padding: 24px;
}
.calc-formula-title {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  color: #1e3a5f;
  margin: 0 0 12px;
}
.calc-formula-code {
  display: block;
  font-family: var(--calc-mono);
  font-size: 13px;
  color: var(--calc-primary);
  line-height: 1.6;
  margin-bottom: 16px;
}
.calc-formula-guide {
  font-size: 12px;
  color: var(--calc-muted);
  line-height: 1.7;
}
.calc-formula-guide ol {
  padding-left: 20px;
  margin: 8px 0;
}
.calc-formula-guide li {
  margin-bottom: 4px;
}
.calc-formula-guide p {
  margin: 8px 0;
}

/* Responsive */
@media (max-width: 768px) {
  .calc-row {
    grid-template-columns: 1fr;
  }
  .calc-material-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .calc-result-panel {
    padding: 24px;
    border-radius: 16px;
  }
  .calc-inputs {
    padding: 16px;
  }
}

@media (max-width: 480px) {
  .calc-mode-switcher {
    width: 100%;
  }
  .calc-mode-btn {
    flex: 1;
    padding: 10px 12px;
    font-size: 13px;
    text-align: center;
  }
}

/* Print styles */
@media print {
  .calc-reset-btn,
  .calc-print-btn,
  .calc-mode-switcher {
    display: none !important;
  }
  .calc-result-panel {
    box-shadow: none;
    border: 2px solid #000;
    color: #000;
    background: #fff;
  }
  .calc-result-number {
    color: #000;
  }
  .calc-breakdown-row span:last-child {
    color: #000;
  }
}