.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 {
    border-radius: 8px;
    border: 1px solid var(--color-border, #e5e7eb);
}

.academic-tool .form-control:focus,
.academic-tool .form-select: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 {
    background: #111827;
    color: var(--color-text, #f9fafb);
    border-color: var(--color-border, #374151);
}

/* --- tool: newton-second-law-calculator --- */
/* 牛顿第二定律计算器样式 */
.newton-calculator-tool {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.calculation-card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.calculation-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.card-header {
    border-radius: 15px 15px 0 0 !important;
    border: none;
    padding: 20px;
}

.input-group-custom {
    border-radius: 10px;
    overflow: hidden;
}

.input-group-custom .form-control {
    border: 2px solid #e9ecef;
    border-right: none;
    padding: 12px 15px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

.input-group-custom .form-control:focus {
    border-color: #0d6efd;
    box-shadow: none;
}

.input-group-custom .input-group-text {
    border: 2px solid #e9ecef;
    border-left: none;
    background-color: #f8f9fa;
    font-weight: 600;
    color: #495057;
}

.btn-calculate {
    border-radius: 10px;
    padding: 12px 30px;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s ease;
    border: none;
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.result-display {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 15px;
    padding: 20px;
    margin-top: 20px;
    border: 2px solid #dee2e6;
}

.formula-display {
    background: linear-gradient(135deg, #fff3cd 0%, #ffeaa7 100%);
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
    border-left: 5px solid #ffc107;
    font-family: 'Courier New', monospace;
    font-weight: bold;
    color: #856404;
}

.preset-button {
    border-radius: 20px;
    padding: 8px 16px;
    margin: 5px;
    font-size: 14px;
    transition: all 0.3s ease;
}

.preset-button:hover {
    transform: scale(1.05);
}

.history-item {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 15px;
    margin-bottom: 10px;
    border-left: 4px solid #0d6efd;
    transition: all 0.3s ease;
}

.history-item:hover {
    background: #e9ecef;
    transform: translateX(5px);
}

.unit-converter {
    background: linear-gradient(135deg, #e3f2fd 0%, #bbdefb 100%);
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
}

.force-icon {
    font-size: 2rem;
    color: #dc3545;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.1); }
    100% { transform: scale(1); }
}

.mass-icon {
    font-size: 2rem;
    color: #198754;
    animation: bounce 2s infinite;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

.acceleration-icon {
    font-size: 2rem;
    color: #0d6efd;
    animation: rotate 3s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@media (max-width: 768px) {
    .newton-calculator-tool {
        padding: 10px;
    }
    
    .calculation-card {
        margin-bottom: 20px;
    }
    
    .btn-calculate {
        padding: 10px 20px;
        font-size: 14px;
    }
}