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

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

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

.academic-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);
}

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

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

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

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

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

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

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

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

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

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

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

/* --- tool: cuboid-surface-area-calculator --- */
.calculator-container {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 15px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
    margin-bottom: 2rem;
}

.calculator-header {
    color: white;
    text-align: center;
    margin-bottom: 2rem;
}

.calculator-header h2 {
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.calculator-header p {
    opacity: 0.9;
    font-size: 1.1rem;
}

.form-card {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.input-group-custom {
    margin-bottom: 1.5rem;
}

.input-group-custom label {
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
    display: block;
}

.input-group-custom input {
    border: 2px solid #e9ecef;
    border-radius: 8px;
    padding: 0.75rem;
    transition: all 0.3s ease;
}

.input-group-custom input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 0.2rem rgba(102, 126, 234, 0.25);
}

.calculate-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
    border-radius: 8px;
    padding: 0.75rem 2rem;
    font-weight: 600;
    transition: all 0.3s ease;
    width: 100%;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.result-section {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 1.5rem;
    margin-top: 2rem;
    border-left: 4px solid #667eea;
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid #e9ecef;
}

.result-item:last-child {
    border-bottom: none;
}

.result-label {
    font-weight: 600;
    color: #495057;
}

.result-value {
    font-weight: 700;
    color: #667eea;
    font-size: 1.1rem;
}

.formula-section {
    background: #e3f2fd;
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    border-left: 4px solid #2196f3;
}

.formula-text {
    font-family: 'Courier New', monospace;
    background: white;
    padding: 0.5rem;
    border-radius: 4px;
    margin: 0.5rem 0;
}

.error-message {
    background: #ffebee;
    color: #c62828;
    border: 1px solid #ffcdd2;
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    display: none;
}

.success-message {
    background: #e8f5e8;
    color: #2e7d32;
    border: 1px solid #c8e6c9;
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    display: none;
}

.dimensions-preview {
    background: #fff3e0;
    border-radius: 8px;
    padding: 1rem;
    margin-top: 1rem;
    border-left: 4px solid #ff9800;
}

.preview-box {
    width: 100px;
    height: 60px;
    background: linear-gradient(45deg, #ff9800, #ff5722);
    border-radius: 4px;
    margin: 0 auto;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 0.8rem;
    text-align: center;
}

.preview-dimensions {
    text-align: center;
    margin-top: 0.5rem;
    font-size: 0.9rem;
    color: #666;
}