.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: moment-of-inertia-calculator --- */
/* 转动惯量计算器样式 */
.moment-inertia-calculator {
    background: linear-gradient(135deg, #74b9ff 0%, #0984e3 100%);
    min-height: auto;
    padding: 2rem 0;
}

.calculation-card {
    border: none;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.calculation-card:hover {
    box-shadow: 0 15px 40px rgba(0,0,0,0.15);
}

.input-group-custom .form-control {
    border-radius: 10px;
    border: 2px solid #e9ecef;
    transition: border-color 0.3s ease;
}

.input-group-custom .form-control:focus {
    border-color: #74b9ff;
    box-shadow: 0 0 0 0.2rem rgba(116, 185, 255, 0.25);
}

.input-group-custom .input-group-text {
    border-radius: 0 10px 10px 0;
    border: 2px solid #e9ecef;
    border-left: none;
    background: #f8f9fa;
    font-weight: 600;
}

.btn-calculate {
    border-radius: 10px;
    padding: 12px 24px;
    font-weight: 600;
    transition: all 0.3s ease;
}

.btn-calculate:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.result-display {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 10px;
    padding: 20px;
    margin-top: 20px;
    border-left: 4px solid #74b9ff;
}

.formula-display {
    background: #fff;
    padding: 15px;
    border-radius: 8px;
    font-family: 'Courier New', monospace;
    font-size: 1.1rem;
    color: #495057;
    border: 1px solid #dee2e6;
    margin-bottom: 15px;
}

.inertia-display {
    color: #74b9ff;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.shape-diagram {
    background: #fff;
    border-radius: 10px;
    padding: 20px;
    margin-top: 20px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    text-align: center;
}

.unit-converter {
    position: relative;
    z-index: 40;
    overflow: visible;
    background: rgba(255,255,255,0.98);
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.shape-select-card {
    position: relative;
    z-index: 1;
}

.moment-inertia-calculator,
.moment-inertia-calculator .row,
.moment-inertia-calculator .col-12,
.moment-inertia-calculator .col-md-4 {
    overflow: visible;
}

/* 自定义单位下拉：避开 body overflow-x:clip 导致原生 select 弹层不可见 */
.unit-dropdown {
    position: relative;
    z-index: 1;
}

.unit-dropdown.is-open {
    z-index: 50;
}

.unit-dropdown-toggle {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    width: 100%;
    min-height: 42px;
    padding: 0.5rem 0.85rem;
    border: 1px solid #ced4da;
    border-radius: 8px;
    background: #fff;
    color: #212529;
    font-size: 1rem;
    line-height: 1.4;
    text-align: left;
    cursor: pointer;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.unit-dropdown-toggle:hover,
.unit-dropdown.is-open .unit-dropdown-toggle {
    border-color: #0984e3;
    box-shadow: 0 0 0 3px rgba(9, 132, 227, 0.18);
}

.unit-dropdown-toggle .bi-chevron-down {
    flex-shrink: 0;
    transition: transform 0.15s ease;
}

.unit-dropdown.is-open .unit-dropdown-toggle .bi-chevron-down {
    transform: rotate(180deg);
}

.unit-dropdown-menu {
    position: absolute;
    left: 0;
    right: 0;
    top: calc(100% + 4px);
    margin: 0;
    padding: 6px;
    list-style: none;
    background: #fff;
    border: 1px solid #dee2e6;
    border-radius: 10px;
    box-shadow: 0 12px 28px rgba(15, 23, 42, 0.18);
    z-index: 60;
    max-height: 240px;
    overflow-y: auto;
}

.unit-dropdown-menu[hidden] {
    display: none !important;
}

.unit-dropdown-menu li {
    display: block;
    padding: 0.55rem 0.75rem;
    border-radius: 8px;
    color: #212529;
    cursor: pointer;
    user-select: none;
}

.unit-dropdown-menu li:hover,
.unit-dropdown-menu li:focus {
    background: #eaf4ff;
    color: #0652a8;
    outline: none;
}

.unit-dropdown-menu li[aria-selected="true"] {
    background: #0984e3;
    color: #fff;
    font-weight: 600;
}

.unit-select-native {
    position: absolute !important;
    width: 1px !important;
    height: 1px !important;
    padding: 0 !important;
    margin: -1px !important;
    overflow: hidden !important;
    clip: rect(0, 0, 0, 0) !important;
    white-space: nowrap !important;
    border: 0 !important;
    opacity: 0 !important;
    pointer-events: none !important;
}

[data-theme="dark"] .moment-inertia-calculator .unit-converter {
    background: rgba(31, 41, 55, 0.98);
}

[data-theme="dark"] .moment-inertia-calculator .unit-converter .form-label {
    color: #f9fafb;
}

[data-theme="dark"] .unit-dropdown-toggle,
[data-theme="dark"] .unit-dropdown-menu {
    background: #111827;
    border-color: #374151;
    color: #f9fafb;
}

[data-theme="dark"] .unit-dropdown-menu li {
    color: #f9fafb;
}

[data-theme="dark"] .unit-dropdown-menu li:hover,
[data-theme="dark"] .unit-dropdown-menu li:focus {
    background: #1f2937;
    color: #93c5fd;
}

.preset-button {
    border-radius: 12px;
    margin: 0;
    min-height: 76px;
    font-weight: 600;
    border-width: 2px;
    transition: all 0.2s ease;
    background: #fff;
    color: #0984e3;
}

.preset-button i {
    font-size: 1.35rem;
    display: block;
    margin-bottom: 4px;
}

.preset-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(9, 132, 227, 0.2);
}

.preset-button.active,
.preset-button.btn-primary {
    background: #0984e3 !important;
    border-color: #0984e3 !important;
    color: #fff !important;
    box-shadow: 0 0 0 3px rgba(9, 132, 227, 0.28), 0 8px 18px rgba(9, 132, 227, 0.25);
    transform: translateY(-1px);
}

.preset-button.active::after {
    content: "已选";
    display: inline-block;
    margin-top: 6px;
    padding: 1px 8px;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 700;
    background: rgba(255, 255, 255, 0.22);
    color: #fff;
}

[data-theme="dark"] .moment-inertia-calculator .preset-button:not(.active) {
    background: #111827;
    color: #74b9ff;
    border-color: #74b9ff;
}

.history-item {
    background: #fff;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 10px;
    border-left: 4px solid #74b9ff;
    transition: all 0.3s ease;
}

.history-item:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.parameter-card {
    background: linear-gradient(135deg, #fff 0%, #f8f9fa 100%);
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.parameter-title {
    color: #74b9ff;
    font-weight: 700;
    margin-bottom: 15px;
    display: flex;
    align-items: center;
}

.parameter-title i {
    margin-right: 10px;
    font-size: 1.2rem;
}

@media (max-width: 768px) {
    .moment-inertia-calculator {
        padding: 1rem 0;
    }
    
    .calculation-card {
        margin-bottom: 20px;
    }
    
    .preset-button {
        width: 100%;
        margin: 5px 0;
    }

    .preset-button.active::after {
        margin-left: 6px;
        margin-top: 0;
    }
}