/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8fafc;
}

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

/* Header and Navigation */
.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: all 0.3s ease;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header.scrolled {
    background: rgba(102, 126, 234, 0.95);
    backdrop-filter: blur(10px);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.logo h1 {
    font-size: 1.8rem;
    font-weight: 700;
    background: linear-gradient(45deg, #fff, #e2e8f0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #e2e8f0;
    transform: translateY(-2px);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #e2e8f0;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

/* Main content */
.main {
    margin-top: 80px;
}

/* Hero section */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 6rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, #fff, #e2e8f0);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
}

.btn-primary {
    background: white;
    color: #667eea;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border-color: white;
}

.btn-secondary:hover {
    background: white;
    color: #667eea;
    transform: translateY(-3px);
}

/* Section styling */
.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 3rem;
    color: #2d3748;
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 2px;
}

/* Calculator section */
.calculator-section {
    padding: 6rem 0;
    background: white;
}

.calculator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.calculator-card {
    background: #f8fafc;
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    border: 1px solid #e2e8f0;
}

.calculator-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0,0,0,0.15);
}

.calculator-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: #2d3748;
    text-align: center;
}

.calc-inputs {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    align-items: center;
}

.calc-inputs input {
    width: 100%;
    max-width: 200px;
    padding: 0.8rem;
    border: 2px solid #e2e8f0;
    border-radius: 10px;
    font-size: 1rem;
    transition: all 0.3s ease;
    text-align: center;
}

.calc-inputs input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.calc-inputs span {
    font-weight: 600;
    color: #4a5568;
}

.calc-btn {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 0.8rem 2rem;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 0.5rem;
}

.calc-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.result {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 10px;
    text-align: center;
    font-weight: 600;
    min-height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.result .success {
    color: #38a169;
    background: #f0fff4;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    border: 1px solid #9ae6b4;
}

.result .error {
    color: #e53e3e;
    background: #fff5f5;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    border: 1px solid #feb2b2;
}

/* Blog section */
.blog-section {
    padding: 6rem 0;
    background: #f8fafc;
}

.blog-article {
    background: white;
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
    max-width: 800px;
    margin: 0 auto;
}

.article-header {
    text-align: center;
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 2px solid #e2e8f0;
}

.article-title {
    font-size: 2.5rem;
    color: #2d3748;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.article-meta {
    display: flex;
    justify-content: center;
    gap: 2rem;
    color: #718096;
    font-size: 0.9rem;
}

.article-content {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #4a5568;
}

.article-content h3 {
    font-size: 1.5rem;
    color: #2d3748;
    margin: 2rem 0 1rem 0;
    position: relative;
    padding-left: 1rem;
}

.article-content h3::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 100%;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 2px;
}

.article-content p {
    margin-bottom: 1.5rem;
}

.article-content ul {
    margin: 1.5rem 0;
    padding-left: 2rem;
}

.article-content li {
    margin-bottom: 0.8rem;
}

.article-content a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    border-bottom: 2px solid transparent;
    transition: all 0.3s ease;
}

.article-content a:hover {
    border-bottom-color: #667eea;
    color: #764ba2;
}

/* About section */
.about-section {
    padding: 6rem 0;
    background: white;
}

.about-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.about-content p {
    font-size: 1.2rem;
    color: #4a5568;
    margin-bottom: 3rem;
    line-height: 1.8;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature {
    background: #f8fafc;
    padding: 2rem;
    border-radius: 15px;
    border: 1px solid #e2e8f0;
    transition: all 0.3s ease;
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}

.feature h3 {
    font-size: 1.3rem;
    color: #2d3748;
    margin-bottom: 1rem;
}

.feature p {
    color: #718096;
    font-size: 1rem;
    margin: 0;
}

/* Footer */
.footer {
    background: #2d3748;
    color: white;
    padding: 3rem 0 1rem 0;
}

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

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: #e2e8f0;
}

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

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

.footer-section a {
    color: #a0aec0;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: #667eea;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #4a5568;
    color: #a0aec0;
}

/* Responsive design */
@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 1rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .calculator-grid {
        grid-template-columns: 1fr;
    }
    
    .blog-article {
        padding: 2rem 1.5rem;
    }
    
    .article-title {
        font-size: 2rem;
    }
    
    .article-meta {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .calc-inputs {
        align-items: stretch;
    }
    
    .calc-inputs input {
        max-width: none;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 4rem 0;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .blog-article {
        padding: 1.5rem 1rem;
    }
    
    .article-content {
        font-size: 1rem;
    }
}

/* Animation classes */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

/* Utility classes */
.text-center {
    text-align: center;
}

.mt-2 {
    margin-top: 1rem;
}

.mb-2 {
    margin-bottom: 1rem;
}