body {
    font-family: 'Poppins', sans-serif;
    background: #f4f7f6;
    color: #333;
    margin: 0;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

.master-controls {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    margin-bottom: 30px;
}

/* Toggle Switch Styles */
.view-toggle {
    display: flex;
    align-items: center;
    gap: 10px;
}
.toggle-label {
    font-weight: 500;
    color: #888;
    transition: color 0.3s ease;
}
.toggle-label.active {
    color: #000;
    font-weight: 600;
}
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}
.switch input { 
    opacity: 0;
    width: 0;
    height: 0;
}
.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 34px;
}
.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}
input:checked + .slider {
    background-color: #3498db;
}
input:checked + .slider:before {
    transform: translateX(26px);
}


#content-select {
    padding: 10px;
    font-size: 16px;
    border-radius: 8px;
    border: 1px solid #ccc;
    min-width: 300px;
    max-width: 90%;
    cursor: pointer;
}

.fields-container {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    align-items: flex-start;
}

.field-card {
    flex: 1;
    min-width: 350px;
    max-width: 400px;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    padding: 20px;
    border-top: 5px solid;
}

.field-card h2 {
    margin-top: 0;
    display: flex;
    align-items: center;
    gap: 10px;
}
.field-card .icon { font-size: 1.5em; }

/* Color Themes */
.gravity { border-color: #2ecc71; } /* Green */
.electricity { border-color: #3498db; } /* Blue */
.magnetism { border-color: #e74c3c; } /* Red */

.content-wrapper .problem-statement {
    font-weight: 500;
    background: #f0f8ff;
    padding: 10px;
    border-radius: 6px;
    border-left: 4px solid #3498db;
    margin-bottom: 15px;
    font-size: 0.95em;
}

.content-wrapper .formula,
.content-wrapper .method {
    background: #f9f9f9;
    padding: 15px;
    border-radius: 8px;
    margin: 15px 0;
}
.content-wrapper .formula {
    font-size: 1.2em;
    text-align: center;
}
.content-wrapper .method h3 {
    margin-top: 0;
    font-size: 1em;
    border-bottom: 2px solid #eee;
    padding-bottom: 5px;
}
.content-wrapper .method p {
    font-size: 0.9em;
    line-height: 1.6;
}

.content-wrapper .analogy {
    font-size: 0.9em;
    line-height: 1.6;
    border-left: 3px solid #eee;
    padding-left: 15px;
    margin: 15px 0;
    min-height: 40px;
}

.calculator {
    margin-top: 20px;
}

.solve-for-group {
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #eee;
}

.solve-for-group legend {
    font-weight: 600;
    font-size: 0.9em;
    color: #555;
}

.solve-for-group .options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 5px;
}

.solve-for-group label {
    font-size: 0.8em;
    cursor: pointer;
}

.input-group {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.input-group label {
    font-weight: 500;
    white-space: nowrap;
    margin-right: 10px;
    font-size: 0.9em;
}

.input-group input {
    width: 120px;
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 6px;
    text-align: right;
    font-size: 1em;
    transition: all 0.2s ease;
}

.input-group input:disabled {
    background-color: #e8f5e9;
    border-color: #4CAF50;
    color: #1b5e20;
    font-weight: bold;
}