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

:root {
    --primary-color: #007BFF;
    --primary-hover: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --light-bg: #f8f9fa;
    --white: #ffffff;
    --text-dark: #333333;
    --text-light: #666666;
    --border-color: #dee2e6;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --shadow-hover: 0 4px 20px rgba(0,0,0,0.15);
}

body {
    font-family: 'Poppins', sans-serif;
    color: var(--text-dark);
    background-color: var(--light-bg);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

html {
    scroll-behavior: smooth;
}

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

/* Header */
.main-header {
    background: var(--white);
    box-shadow: var(--shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.logo h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
    margin: 0;
}

.logo a {
    text-decoration: none;
    color: inherit;
}

.main-nav {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.main-nav a {
    color: var(--text-dark);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.main-nav a:hover {
    color: var(--primary-color);
}

.lang-switcher {
    display: flex;
    gap: 0.5rem;
    border-left: 2px solid var(--border-color);
    padding-left: 1rem;
}

.lang-switcher a {
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.875rem;
}

.lang-switcher a.active {
    background: var(--primary-color);
    color: var(--white);
}

/* Main Content */
.main-content {
    flex: 1;
    width: 100%;
    padding: 2rem 0;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 3rem 0 2rem;
    max-width: 100%;
}

.hero h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero .subtitle {
    font-size: 1.25rem;
    color: var(--text-dark);
    margin-bottom: 1rem;
    font-weight: 500;
}

.hero .description {
    font-size: 1rem;
    color: var(--text-light);
    max-width: 800px;
    margin: 0 auto;
}

/* Calculator Section */
.calculator-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
    margin: 2rem 0;
    width: 100%;
    max-width: 100%;
}

.calculator-card,
.result-card {
    background: var(--white);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--shadow);
}

.calculator-card h2,
.result-card h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.75rem;
}

/* Form */
.tax-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input,
.form-group select {
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    font-family: 'Poppins', sans-serif;
    transition: border-color 0.3s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.form-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    box-shadow: var(--shadow-hover);
}

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

.btn-secondary:hover {
    background: #5a6268;
}

/* Result */
.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.result-item {
    padding: 1rem;
    background: var(--light-bg);
    border-radius: 8px;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.result-item.highlight {
    background: #fff3cd;
    border-left: 4px solid #ffc107;
}

.result-item.success {
    background: #d4edda;
    border-left: 4px solid var(--success-color);
}

.result-label {
    font-size: 0.875rem;
    color: var(--text-light);
    font-weight: 500;
}

.result-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-dark);
}

.result-description {
    margin-top: 1rem;
    padding: 1rem;
    background: var(--light-bg);
    border-radius: 8px;
}

.result-description h3 {
    font-size: 1.125rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.result-actions {
    margin-top: 1.5rem;
}

/* Features Section */
.features-section,
.how-section {
    margin: 3rem 0;
    text-align: center;
    width: 100%;
    max-width: 100%;
}

.features-section h2,
.how-section h2 {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 2rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.feature-item {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
    transition: transform 0.3s;
}

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

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

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

.step-item {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow);
}

.step-number {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 600;
    margin: 0 auto 1rem;
}

/* Alerts */
.alert {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.alert-error {
    background: #f8d7da;
    color: #721c24;
    border-left: 4px solid var(--danger-color);
}

/* AdSense */
.ad-container {
    margin: 2rem 0;
    text-align: center;
}

/* Footer */
.main-footer {
    background: var(--text-dark);
    color: var(--white);
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

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

.footer-section h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section a {
    color: var(--white);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 1.75rem;
    }
    
    .hero .subtitle {
        font-size: 1.1rem;
    }
    
    .hero {
        padding: 2rem 0 1.5rem;
    }
    
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .main-nav {
        flex-direction: column;
        gap: 0.5rem;
        width: 100%;
    }
    
    .lang-switcher {
        border-left: none;
        border-top: 2px solid var(--border-color);
        padding-left: 0;
        padding-top: 0.5rem;
        margin-top: 0.5rem;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .result-grid {
        grid-template-columns: 1fr;
    }
    
    .features-grid,
    .steps-grid {
        grid-template-columns: 1fr;
    }
    
    .container {
        padding: 0 15px;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.5rem;
    }
    
    .hero .subtitle {
        font-size: 1rem;
    }
    
    .calculator-card,
    .result-card {
        padding: 1.5rem;
    }
    
    .feature-item,
    .step-item {
        padding: 1.5rem;
    }
}