:root {
    --primary-color: #007AFF;
    --secondary-color: #5AC8FA;
    --success-color: #34C759;
    --danger-color: #FF3B30;
    --background-color: #F2F2F7;
    --card-background: #FFFFFF;
    --text-primary: #000000;
    --text-secondary: #6C6C70;
    --border-color: #E5E5EA;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 24px rgba(0, 0, 0, 0.15);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px 0;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.calculator-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 40px;
}

.input-section, .results-section {
    background: var(--card-background);
    padding: 30px;
    border-radius: 16px;
    box-shadow: var(--shadow);
}

h2 {
    font-size: 1.5rem;
    margin-bottom: 25px;
    color: var(--text-primary);
}

.input-group {
    margin-bottom: 20px;
    position: relative;
}

label {
    display: block;
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-primary);
}

input[type="number"] {
    width: calc(100% - 60px);
    padding: 12px 16px;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    background: var(--card-background);
    transition: all 0.3s ease;
}

input[type="number"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

.unit {
    position: absolute;
    right: 16px;
    top: 42px;
    color: var(--text-secondary);
    font-weight: 500;
}

.calculate-btn {
    width: 100%;
    padding: 16px;
    font-size: 1.1rem;
    font-weight: 600;
    color: white;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 30px;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.calculate-btn:active {
    transform: translateY(0);
}

.result-card {
    background: var(--background-color);
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 16px;
    transition: all 0.3s ease;
}

.result-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
}

.result-card h3 {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
    font-weight: 500;
}

.result-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
}

.result-value.secondary {
    font-size: 1.4rem;
    color: var(--text-primary);
}

.result-value.positive {
    color: var(--success-color);
}

.result-value.negative {
    color: var(--danger-color);
}

.advice {
    padding: 20px;
    background: linear-gradient(135deg, rgba(0, 122, 255, 0.1), rgba(90, 200, 250, 0.1));
    border-radius: 12px;
    margin-top: 20px;
    font-weight: 500;
    line-height: 1.8;
    color: var(--text-primary);
}

.chart-section {
    background: var(--card-background);
    padding: 30px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    height: 400px;
}

#assetChart {
    width: 100% !important;
    height: 320px !important;
}

footer {
    text-align: center;
    padding: 40px 0;
    color: var(--text-secondary);
}

.language-selector {
    margin-bottom: 20px;
}

#languageSelect {
    padding: 8px 16px;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background: var(--card-background);
    cursor: pointer;
    transition: all 0.3s ease;
}

#languageSelect:hover {
    border-color: var(--primary-color);
}

@media (max-width: 768px) {
    .calculator-section {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .input-section, .results-section {
        padding: 20px;
    }
    
    .result-value {
        font-size: 1.5rem;
    }
    
    .chart-section {
        height: 350px;
    }
    
    #assetChart {
        height: 270px !important;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    input[type="number"] {
        font-size: 16px;
    }
}