* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
    border-bottom: 1px solid #e1e4e8;
}

header h1 {
    color: #0d47a1;
    margin-bottom: 10px;
}

.calculator-card {
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    display: flex;
    flex-direction: column;
    margin-bottom: 30px;
}

@media (min-width: 768px) {
    .calculator-card {
        flex-direction: row;
    }
}

.input-section, .results-section {
    padding: 25px;
}

.input-section {
    background-color: #f9fafc;
    flex: 1;
}

.results-section {
    flex: 1;
    background-color: white;
    border-top: 1px solid #e1e4e8;
}

@media (min-width: 768px) {
    .results-section {
        border-top: none;
        border-left: 1px solid #e1e4e8;
    }
}

h2 {
    margin-bottom: 20px;
    color: #0d47a1;
    font-size: 1.5rem;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
}

input[type="date"],
input[type="number"] {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 16px;
}

button {
    background-color: #0d47a1;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    transition: background-color 0.3s;
    width: 100%;
    margin-top: 10px;
}

button:hover {
    background-color: #0a3880;
}

.result-item {
    display: flex;
    justify-content: space-between;
    padding: 12px 0;
    border-bottom: 1px solid #eee;
}

.result-item .label {
    font-weight: 500;
}

.result-item .value {
    font-weight: 600;
}

.highlight {
    background-color: #e3f2fd;
    padding: 12px;
    border-radius: 4px;
    margin-top: 10px;
    border: none;
}

.highlight .label {
    color: #0d47a1;
}

.highlight .value {
    color: #0d47a1;
    font-size: 1.1rem;
}

footer {
    text-align: center;
    color: #666;
    font-size: 0.9rem;
    padding: 20px 0;
}

.stock-prices {
    margin-top: 25px;
    padding-top: 20px;
    border-top: 1px solid #e1e4e8;
}

.stock-prices h3 {
    color: #0d47a1;
    font-size: 1.2rem;
    margin-bottom: 15px;
}

.contribution-section {
    margin-bottom: 25px;
    padding: 20px;
    background-color: #f0f4f8;
    border-radius: 8px;
    border: 1px solid #e1e4e8;
}

.mode-toggle {
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.toggle-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;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: .4s;
}

input:checked + .slider {
    background-color: #0d47a1;
}

input:focus + .slider {
    box-shadow: 0 0 1px #0d47a1;
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

.mode-label {
    font-size: 0.9rem;
    color: #666;
}

.contribution-mode {
    transition: opacity 0.3s ease-in-out;
}

.contribution-mode.hidden {
    display: none;
}

.help-text {
    display: block;
    margin-top: 5px;
    color: #666;
    font-size: 0.85rem;
    font-style: italic;
}

.date-link {
    color: #0d47a1;
    text-decoration: underline;
    cursor: pointer;
    transition: all 0.2s ease;
    padding: 2px 4px;
    border-radius: 3px;
    display: inline-block;
}

.date-link:hover {
    color: #1565c0;
    background-color: #e3f2fd;
    text-decoration: none;
}