.tool-fullwidth {
    width: 100%;
    max-width: 100%;
    margin: 0;
    padding: 0;
}

/* Tool shell */
.engineering-tool {
    max-width: 100%;
    margin: 0 auto;
}

.engineering-tool .editor-section,
.editor-section.engineering-tool {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.engineering-tool .card:not(.result-card) {
    border: 1px solid var(--color-border, #e5e7eb);
    box-shadow: var(--shadow-sm, 0 1px 3px rgba(0, 0, 0, 0.06));
    border-radius: var(--radius, 12px);
    background: var(--color-surface, #fff);
}

.engineering-tool .card-body {
    padding: 1.25rem 1.35rem;
}

.engineering-tool .card-title {
    color: var(--color-text, #1f2937);
    font-weight: 700;
    font-size: 1.05rem;
}

.engineering-tool .form-control,
.engineering-tool .form-select,
.engineering-tool .select-input {
    border-radius: 8px;
    border: 1px solid var(--color-border, #e5e7eb);
}

.engineering-tool .form-control:focus,
.engineering-tool .form-select:focus {
    border-color: var(--color-primary, #0d9488);
    box-shadow: 0 0 0 3px rgba(13, 148, 136, 0.15);
}

.engineering-tool .btn-primary {
    background: var(--color-primary, #0d9488);
    border-color: var(--color-primary, #0d9488);
}

.engineering-tool .btn-primary:hover {
    background: var(--color-primary-hover, #0f766e);
    border-color: var(--color-primary-hover, #0f766e);
}

.engineering-tool .alert {
    border-radius: 10px;
}

[data-theme="dark"] .engineering-tool .card:not(.result-card) {
    background: var(--color-surface, #1f2937);
    border-color: var(--color-border, #374151);
}

[data-theme="dark"] .engineering-tool .card-title,
[data-theme="dark"] .engineering-tool .form-label,
[data-theme="dark"] .engineering-tool {
    color: var(--color-text, #f9fafb);
}

[data-theme="dark"] .engineering-tool .text-muted,
[data-theme="dark"] .engineering-tool .form-text {
    color: var(--color-text-secondary, #9ca3af) !important;
}

[data-theme="dark"] .engineering-tool .form-control,
[data-theme="dark"] .engineering-tool .form-select {
    background: #111827;
    color: var(--color-text, #f9fafb);
    border-color: var(--color-border, #374151);
}

/* --- tool: pipe-volume-calculator --- */
.pipe-calculator {
    background: linear-gradient(135deg, #e3f2fd 0%, #f3e5f5 100%);
    min-height: auto;
    padding: 2rem 0;
}

.calculator-container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    padding: 2rem;
    margin: 2rem 0;
}

.calculator-title {
    color: #424242;
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    text-align: center;
}

.known-section {
    margin-bottom: 2rem;
}

.known-label {
    color: #666;
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.known-select {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    background: white;
    color: #666;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.known-select:focus {
    outline: none;
    border-color: #2196f3;
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.input-group {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.input-section {
    flex: 1;
}

.input-label {
    color: #666;
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
    display: block;
}

.input-field {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e0e0e0;
    border-radius: 12px;
    background: white;
    color: #333;
    font-size: 1rem;
    text-align: center;
    transition: all 0.3s ease;
}

.input-field:focus {
    outline: none;
    border-color: #2196f3;
    box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.1);
}

.button-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.btn-increment, .btn-decrement {
    width: 32px;
    height: 32px;
    border: none;
    border-radius: 8px;
    background: #f5f5f5;
    color: #666;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-increment:hover, .btn-decrement:hover {
    background: #e0e0e0;
    color: #333;
}

.btn-increment:active, .btn-decrement:active {
    background: #2196f3;
    color: white;
}

.calculate-btn {
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, #2196f3, #1976d2);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 2rem;
}

.calculate-btn:hover {
    background: linear-gradient(135deg, #1976d2, #1565c0);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(33, 150, 243, 0.3);
}

.result-section {
    margin-top: 2rem;
    padding: 1.5rem;
    background: #f8f9fa;
    border-radius: 12px;
    display: none;
}

.result-title {
    color: #333;
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.result-value {
    color: #2196f3;
    font-size: 2rem;
    font-weight: bold;
    text-align: center;
    margin-bottom: 0.5rem;
}

.result-unit {
    color: #666;
    font-size: 1rem;
    text-align: center;
}

.formula-section {
    margin-top: 2rem;
    padding: 1.5rem;
    background: #e8f5e8;
    border-radius: 12px;
}

.formula-title {
    color: #2e7d32;
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.formula-text {
    color: #424242;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

@media (max-width: 768px) {
    .input-group {
        flex-direction: column;
        gap: 1rem;
    }
    
    .button-group {
        flex-direction: row;
        justify-content: center;
    }
}