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

:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #10b981;
    --danger-color: #ef4444;
    --background: #ffffff;
    --surface: #f9fafb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --radius: 0.5rem;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--surface);
    color: var(--text-primary);
    line-height: 1.5;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.header {
    background-color: var(--background);
    padding: 2rem 0;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.language-selector {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

.lang-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background-color: var(--background);
    color: var(--text-primary);
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.875rem;
}

.lang-btn:hover {
    background-color: var(--surface);
}

.lang-btn.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

main {
    padding: 2rem 0;
}

.input-section, .results-section, .preset-recipes {
    margin-bottom: 3rem;
}

.servings-control {
    background-color: var(--background);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.servings-control label {
    font-weight: 500;
    color: var(--text-secondary);
}

.servings-control input {
    width: 80px;
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
    text-align: center;
}

.ingredients-input {
    background-color: var(--background);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.ingredients-input h2, .scaled-results h2, .unit-converter h2, .shopping-list h2, .preset-recipes h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.ingredients-list {
    margin-bottom: 1rem;
}

.ingredient-row {
    display: grid;
    grid-template-columns: 2fr 1fr 120px auto;
    gap: 0.5rem;
    margin-bottom: 0.75rem;
    align-items: center;
}

.ingredient-name, .ingredient-amount, .ingredient-unit {
    padding: 0.625rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
}

.ingredient-name:focus, .ingredient-amount:focus, .ingredient-unit:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.remove-btn {
    padding: 0.625rem 1rem;
    background-color: var(--danger-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.2s;
}

.remove-btn:hover {
    background-color: #dc2626;
}

.add-btn, .action-btn, .preset-btn {
    padding: 0.75rem 1.5rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-weight: 500;
    transition: background-color 0.2s;
    font-size: 1rem;
}

.add-btn:hover, .action-btn:hover, .preset-btn:hover {
    background-color: var(--primary-hover);
}

.results-section {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.scaled-results, .unit-converter, .shopping-list {
    background-color: var(--background);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.scaled-list {
    max-height: 300px;
    overflow-y: auto;
}

.scaled-item {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.scaled-item:last-child {
    border-bottom: none;
}

.converter-controls {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.converter-controls input, .converter-controls select {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
}

.conversion-result {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--secondary-color);
    padding: 0.5rem 0;
}

.shopping-list-content {
    white-space: pre-line;
    padding: 1rem;
    background-color: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    margin-bottom: 1rem;
    min-height: 150px;
    max-height: 300px;
    overflow-y: auto;
}

.action-buttons {
    display: flex;
    gap: 0.5rem;
}

.preset-recipes {
    background-color: var(--background);
    padding: 1.5rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.preset-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.preset-btn {
    background-color: var(--secondary-color);
}

.preset-btn:hover {
    background-color: #059669;
}

.footer {
    background-color: var(--background);
    padding: 2rem 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    margin-top: 4rem;
}

/* レスポンシブデザイン */
@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .ingredient-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .servings-control {
        flex-direction: column;
        align-items: stretch;
    }
    
    .servings-control input {
        width: 100%;
    }
    
    .converter-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .converter-controls input,
    .converter-controls select {
        width: 100%;
    }
    
    .action-buttons {
        flex-direction: column;
    }
}

/* スクロールバーのカスタマイズ */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--surface);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* アニメーション */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.ingredient-row {
    animation: fadeIn 0.3s ease-out;
}