:root {
    --primary-blue: #007bff;
    --dark-blue: #0a1128;
    --light-blue: #00d4ff;
    --text-color: #ffffff;
    --card-background: #ffffff;
    --border-color: rgba(255, 255, 255, 0.1);
    --gray-text: #6c757d;
    --accent-blue: #00d4ff;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--dark-blue);
    min-height: 100vh;
    font-size: 16px;
}

/* Modern scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

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

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

::-webkit-scrollbar-thumb:hover {
    background: #00b8e6;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
    color: var(--text-color);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    color: var(--text-color);
    letter-spacing: -0.02em;
}

h2 {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    color: var(--text-color);
    letter-spacing: -0.01em;
}

h3 {
    font-size: clamp(1.4rem, 3vw, 2rem);
    color: var(--text-color);
    letter-spacing: -0.01em;
}

h4 {
    font-size: 1.25rem;
    color: var(--text-color);
    font-weight: 600;
}

p {
    margin-bottom: 1rem;
    color: var(--gray-text);
}

a {
    color: var(--light-blue);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #00b8e6;
}

/* Header & Navigation */
.header {
    background: var(--dark-blue);
    color: var(--text-color);
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.nav-brand .brand-link {
    display: flex;
    align-items: center;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-color);
    text-decoration: none;
}

.nav-brand .brand-link strong {
    margin-left: 0.5rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    align-items: center;
}

.nav-menu li {
    margin-right: 1rem;
}

.nav-menu li:last-child {
    margin-right: 0;
}

.nav-link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.75rem;
    padding: 0.5rem 0;
    position: relative;
    transition: color 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.nav-link::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-blue);
    transition: width 0.3s ease;
}

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

.nav-link:hover {
    color: var(--light-blue);
}

.nav-link.active {
    color: var(--primary-blue);
}

.nav-cta {
    background: var(--primary-blue);
    color: var(--text-color);
    padding: 0.6rem 1.2rem;
    border-radius: 0.375rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    margin-left: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-size: 0.8rem;
}

.nav-cta:hover {
    background: var(--light-blue);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(0, 212, 255, 0.2);
}

/* Mobile Navigation */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.4rem;
}

.hamburger-line {
    width: 20px;
    height: 2px;
    background: #ffffff;
    margin: 2px 0;
    transition: all 0.3s ease;
    border-radius: 2px;
}

.mobile-nav {
    display: none;
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 350px;
    height: 100vh;
    background: rgba(26, 26, 26, 0.98);
    backdrop-filter: blur(10px);
    transition: right 0.3s ease;
    z-index: 999;
    overflow-y: auto;
}

.mobile-nav.active {
    right: 0;
}

.mobile-nav-menu {
    list-style: none;
    padding: 4rem 1.5rem 1.5rem;
}

.mobile-nav-link {
    display: block;
    color: #b0b0b0;
    font-weight: 500;
    padding: 0.75rem;
    border-radius: 0.375rem;
    margin-bottom: 0.5rem;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
    color: #ffffff;
    background: rgba(79, 195, 247, 0.1);
}

.mobile-nav-cta {
    background: linear-gradient(135deg, #4fc3f7 0%, #29b6f6 100%);
    color: #ffffff !important;
    margin-top: 1rem;
}

/* Hero Section */
.hero {
    padding: 6rem 2rem;
    text-align: center;
    max-width: 1200px;
    margin: 0 auto;
    min-height: 70vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.hero h1 {
    margin-bottom: 1.5rem;
    color: var(--text-color);
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 700;
    line-height: 1.1;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--gray-text);
    margin-bottom: 2.5rem;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    line-height: 1.6;
}

.hero-cta {
    display: inline-block;
    background: var(--primary-blue);
    color: var(--text-color);
    padding: 1rem 2rem;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all 0.3s ease;
    text-decoration: none;
    border: none;
    cursor: pointer;
}

.hero-cta:hover {
    background: var(--light-blue);
    transform: translateY(-2px);
    box-shadow: 0 15px 35px rgba(0, 212, 255, 0.3);
}

/* Calculator Section */
.calculator-section {
    padding: 4rem 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.calculator-container {
    background: var(--card-background);
    backdrop-filter: blur(10px);
    border-radius: 1rem;
    padding: 3rem;
    border: 1px solid var(--border-color);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    color: #333;
}

.calculator-container h2 {
    color: #333;
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.calculator-container p {
    color: var(--gray-text);
    margin-bottom: 2rem;
    font-size: 1rem;
}

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

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #333;
    font-size: 1rem;
}

.form-input,
.form-select {
    width: 100%;
    padding: 1rem;
    background: #f8f9fa;
    border: 2px solid #e9ecef;
    border-radius: 0.5rem;
    color: #333;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-input:focus,
.form-select:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
    background: #ffffff;
}

.form-input::placeholder {
    color: #999;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

.calculate-btn {
    width: 100%;
    background: var(--primary-blue);
    color: var(--text-color);
    padding: 1rem 2rem;
    border: none;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.3s ease;
}

.calculate-btn:hover {
    background: var(--light-blue);
    transform: translateY(-2px);
    box-shadow: 0 15px 35px rgba(0, 212, 255, 0.3);
}

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

/* Results Section */
.results {
    margin-top: 2rem;
    padding: 2rem;
    background: rgba(0, 123, 255, 0.1);
    border-radius: 0.5rem;
    border: 1px solid var(--primary-blue);
    display: none;
}

.results.show {
    display: block;
}

.result-value {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--primary-blue);
    margin-bottom: 0.5rem;
}

.result-label {
    color: #333;
    margin-bottom: 1rem;
    font-size: 1rem;
}

.result-breakdown {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-top: 1.5rem;
}

.breakdown-item {
    text-align: center;
    padding: 1.5rem;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 0.5rem;
    border: 1px solid #e9ecef;
}

.breakdown-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 0.5rem;
}

.breakdown-label {
    font-size: 0.9rem;
    color: var(--gray-text);
}

/* Content Sections */
.content-section {
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.content-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.content-card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border-radius: 1rem;
    padding: 2rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: transform 0.3s ease;
}

.content-card:hover {
    transform: translateY(-5px);
    background: rgba(255, 255, 255, 0.08);
}

.content-card h3 {
    margin-bottom: 1rem;
    color: var(--accent-blue);
    font-size: 1.3rem;
}

.content-card p,
.content-card li {
    color: #b0b0b0;
    font-size: 1rem;
}

/* FAQ Section */
.faq-section {
    padding: 4rem 2rem;
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border-radius: 0.75rem;
    margin-bottom: 1rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
    overflow: hidden;
}

.faq-question {
    width: 100%;
    background: none;
    border: none;
    padding: 1.5rem;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 600;
    color: #ffffff;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s ease;
}

.faq-question:hover {
    background: rgba(0, 212, 255, 0.1);
}

.faq-icon {
    transition: transform 0.3s ease;
    font-size: 1.5rem;
    color: var(--accent-blue);
}

.faq-item.active .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
    color: #b0b0b0;
}

.faq-item.active .faq-answer {
    padding: 0 1.5rem 1.5rem;
    max-height: 500px;
}

/* Footer */
.footer {
    background: rgba(26, 26, 26, 0.95);
    border-top: 1px solid #333;
    padding: 2.5rem 1.5rem 1rem;
    margin-top: 3rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 0.75rem;
    color: #4fc3f7;
    font-size: 1rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.4rem;
}

.footer-links a {
    color: #b0b0b0;
    transition: color 0.3s ease;
    font-size: 0.9rem;
}

.footer-links a:hover {
    color: #4fc3f7;
}

.footer-description,
.safety-disclaimer {
    color: #b0b0b0;
    line-height: 1.5;
    font-size: 0.9rem;
}

.footer-bottom {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid #333;
}

.copyright {
    color: #666;
    font-size: 0.8rem;
}

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

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

.mb-3 {
    margin-bottom: 3rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .desktop-nav {
        display: none;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .mobile-nav {
        display: block;
    }
    
    .nav-container {
        padding: 0.75rem 1rem;
    }
    
    .hero {
        padding: 2rem 1rem;
    }
    
    .calculator-section {
        padding: 1.5rem 1rem;
    }
    
    .calculator-container {
        padding: 1.5rem;
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .content-section {
        padding: 2rem 1rem;
    }
    
    .faq-section {
        padding: 2rem 1rem;
    }
    
    .footer {
        padding: 2rem 1rem 1rem;
    }
    
    .footer-container {
        grid-template-columns: 1fr;
        gap: 1.25rem;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .calculator-container {
        padding: 1rem;
    }
    
    .result-value {
        font-size: 1.75rem;
    }
    
    .result-breakdown {
        grid-template-columns: 1fr;
    }
    
    .content-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .content-card {
        padding: 1.25rem;
    }
    
    .mobile-nav {
        width: 90%;
        max-width: 300px;
    }
}

/* Animation Classes */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Focus States for Accessibility */
.nav-link:focus,
.nav-cta:focus,
.mobile-nav-link:focus,
.mobile-nav-cta:focus,
.calculate-btn:focus,
.faq-question:focus {
    outline: 2px solid #4fc3f7;
    outline-offset: 2px;
}

/* Modern button enhancements */
.calculate-btn {
    position: relative;
    overflow: hidden;
}

.calculate-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.calculate-btn:hover::before {
    left: 100%;
}

/* Enhanced card hover effects */
.content-card {
    position: relative;
    overflow: hidden;
}

.content-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, #4fc3f7, #29b6f6);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.content-card:hover::before {
    transform: scaleX(1);
}

/* Smooth transitions */
* {
    transition: color 0.3s ease, background-color 0.3s ease, border-color 0.3s ease, transform 0.3s ease;
}

/* Print Styles */
@media print {
    .header,
    .mobile-nav,
    .footer,
    .hero-cta {
        display: none;
    }
    
    body {
        background: #ffffff;
        color: #000000;
    }
    
    .calculator-container {
        border: 1px solid #000;
        background: #ffffff;
    }
}