* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', system-ui, sans-serif;
}

body {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    min-height: 100vh;
    padding: 2rem;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.header {
    background: linear-gradient(to right, #3498db, #2980b9);
    color: white;
    padding: 1.5rem;
    text-align: center;
}

.tabs {
    display: flex;
    background: #f8f9fa;
    padding: 0.5rem;
    gap: 0.5rem;
    border-bottom: 1px solid #dee2e6;
}

.tab {
    padding: 0.75rem 1.5rem;
    border: none;
    background: none;
    cursor: pointer;
    border-radius: 8px;
    font-weight: 500;
    color: #495057;
    transition: all 0.3s ease;
}

.tab:hover {
    background: rgba(52, 152, 219, 0.1);
}

.tab.active {
    background: #3498db;
    color: white;
}

.tab-content {
    display: none;
    padding: 2rem;
}

.tab-content.active {
    display: block;
}

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

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: #2c3e50;
    font-weight: 500;
}

select,
input {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

select:focus,
input:focus {
    outline: none;
    border-color: #3498db;
}

.limits-container {
    display: grid;
    gap: 1rem;
    margin: 1rem 0;
}

.limit-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.helper-text {
    font-size: 0.875rem;
    color: #6c757d;
    margin-top: 0.5rem;
}

.button {
    background: #3498db;
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    width: 100%;
    transition: background 0.3s ease;
}

.button:hover {
    background: #2980b9;
}

.result {
    margin-top: 1.5rem;
    padding: 1rem;
    background: #f8f9fa;
    border-radius: 8px;
    text-align: center;
}

.result span {
    font-weight: bold;
    color: #2c3e50;
}

.card {
    background: white;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.formula-list {
    list-style: none;
}

.formula-list li {
    padding: 0.75rem;
    border-bottom: 1px solid #eee;
}

.formula-list li:last-child {
    border-bottom: none;
}

.examples-list li {
    margin-bottom: 1rem;
    padding: 1rem;
    background: #f8f9fa;
    border-radius: 8px;
}

.method-description {
    margin-bottom: 1rem;
    line-height: 1.6;
}