.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: trapezoidal-area-calculator --- */
.trapezoid-calculator {
    max-width: 800px;
    margin: 0 auto;
}

.trapezoid-diagram {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 30px;
    border: 1px solid #dee2e6;
}

.trapezoid-shape {
    width: 200px;
    height: 120px;
    background: linear-gradient(135deg, #007bff 0%, #0056b3 100%);
    clip-path: polygon(20% 0%, 80% 0%, 100% 100%, 0% 100%);
    margin: 0 auto 15px;
    position: relative;
}

.trapezoid-labels {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 10px;
    font-size: 14px;
    color: #6c757d;
}

.trapezoid-labels .label {
    text-align: center;
    flex: 1;
}

.form-section {
    background: #fff;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 25px;
}

.result-section {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    border-radius: 12px;
    padding: 25px;
    text-align: center;
    display: none;
}

.result-section.show {
    display: block;
    animation: fadeInUp 0.5s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.area-result {
    font-size: 2.5rem;
    font-weight: bold;
    margin: 15px 0;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.calculation-steps {
    background: rgba(255,255,255,0.2);
    border-radius: 8px;
    padding: 15px;
    margin-top: 15px;
    text-align: left;
}

.step-item {
    margin-bottom: 8px;
    padding: 5px 0;
    border-bottom: 1px solid rgba(255,255,255,0.2);
}

.step-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
}

.input-group-custom {
    position: relative;
}

.input-group-custom .form-control {
    padding-right: 40px;
}

.input-group-custom .unit {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: #6c757d;
    font-weight: 500;
}

.unit-selector {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 20px;
    border: 1px solid #dee2e6;
}

.unit-selector label {
    font-weight: 600;
    color: #495057;
    margin-bottom: 8px;
}

.btn-calculate {
    background: linear-gradient(135deg, #007bff 0%, #0056b3 100%);
    border: none;
    padding: 12px 30px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0,123,255,0.4);
}

.alert-custom {
    border-radius: 8px;
    border: none;
    padding: 12px 20px;
}

@media (max-width: 768px) {
    .trapezoid-shape {
        width: 150px;
        height: 90px;
    }
    
    .area-result {
        font-size: 2rem;
    }
}