:root {
    --primary-color: #5e72e4;
    --primary-dark: #4c63d2;
    --secondary-color: #f5365c;
    --success-color: #2dce89;
    --warning-color: #fb6340;
    --info-color: #11cdef;
    --text-primary: #32325d;
    --text-secondary: #8898aa;
    --border-color: #e9ecef;
    --background: #f8f9fe;
    --card-background: #ffffff;
    --shadow-sm: 0 0 .5rem rgba(0, 0, 0, .075);
    --shadow-md: 0 0 1rem rgba(0, 0, 0, .15);
    --shadow-lg: 0 0 3rem rgba(50, 50, 93, .1), 0 0 1.5rem rgba(0, 0, 0, .08);
    --border-radius: 0.375rem;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(150deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    padding: 3rem 0;
    color: white;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.95;
    margin-bottom: 2rem;
}

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

.lang-btn {
    padding: 0.5rem 1rem;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 500;
    backdrop-filter: blur(10px);
}

.lang-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

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

main {
    background: var(--card-background);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    margin-bottom: 3rem;
}

.calculator-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: none;
    color: var(--text-secondary);
    border: none;
    border-bottom: 3px solid transparent;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    font-weight: 500;
    margin-bottom: -2px;
}

.tab-btn:hover {
    color: var(--primary-color);
}

.tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.tab-content {
    display: none;
    animation: fadeIn 0.3s ease-in-out;
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.calculator-section {
    max-width: 600px;
    margin: 0 auto;
}

.calculator-section h2 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.description {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 1rem;
}

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

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-primary);
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
    background: white;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(94, 114, 228, 0.25);
}

.input-group span {
    display: inline-block;
    padding: 0 0.5rem;
    font-weight: 500;
}

.calculate-btn {
    width: 100%;
    padding: 1rem;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 6px rgba(50, 50, 93, 0.11), 0 1px 3px rgba(0, 0, 0, 0.08);
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 7px 14px rgba(50, 50, 93, 0.1), 0 3px 6px rgba(0, 0, 0, 0.08);
}

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

.result-container {
    margin-top: 2rem;
}

.result-success {
    padding: 1.5rem;
    background: linear-gradient(135deg, #f5f7fa 0%, #e9ecef 100%);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--success-color);
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.result-success h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
    font-size: 1.25rem;
}

.result-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

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

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

.result-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.error {
    padding: 1rem;
    background: #fef2f2;
    color: #dc2626;
    border-radius: var(--border-radius);
    border-left: 4px solid #dc2626;
    animation: shake 0.3s ease-in-out;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.preset-buttons {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.preset-btn {
    padding: 0.5rem 1rem;
    background: var(--background);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
    font-weight: 500;
}

.preset-btn:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.ingredients-list {
    margin-bottom: 1.5rem;
}

.ingredients-list h3 {
    margin-bottom: 1rem;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.ingredient-row {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr auto;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.ingredient-row input {
    padding: 0.5rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 0.9rem;
}

.remove-ingredient-btn {
    padding: 0.5rem 0.75rem;
    background: var(--secondary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: bold;
}

.remove-ingredient-btn:hover {
    background: #d32f4f;
}

.add-ingredient-btn {
    padding: 0.75rem 1.5rem;
    background: var(--success-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.add-ingredient-btn:hover {
    background: #26b577;
}

.ingredients-result {
    margin-top: 1rem;
}

.ingredient-result-row {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem;
    background: white;
    border-radius: var(--border-radius);
    margin-bottom: 0.5rem;
}

.ingredient-name-result {
    font-weight: 500;
    color: var(--text-primary);
}

.ingredient-amount-result {
    color: var(--primary-color);
    font-weight: 600;
}

.scale-mode-selector {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.mode-btn {
    flex: 1;
    padding: 0.75rem;
    background: var(--background);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

.mode-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

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

.features {
    margin-top: 4rem;
    padding-top: 3rem;
    border-top: 1px solid var(--border-color);
}

.features h2 {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    text-align: center;
    padding: 2rem;
    background: var(--background);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

footer {
    text-align: center;
    padding: 2rem;
    color: white;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    main {
        padding: 1.5rem;
    }
    
    .calculator-tabs {
        gap: 0.25rem;
    }
    
    .tab-btn {
        padding: 0.5rem 1rem;
        font-size: 0.9rem;
    }
    
    .ingredient-row {
        grid-template-columns: 1fr;
        gap: 0.5rem;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.75rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .calculator-section h2 {
        font-size: 1.5rem;
    }
    
    .language-selector {
        justify-content: center;
    }
    
    .lang-btn {
        padding: 0.4rem 0.8rem;
        font-size: 0.85rem;
    }
}