/* ==================== CSS Variables ==================== */
:root {
    /* Colors - Tennis-themed vibrant palette */
    --primary: #00C853;
    --primary-dark: #00A344;
    --primary-light: #69F0AE;
    --secondary: #FFD600;
    --secondary-dark: #FFC400;
    
    --bg-primary: #0A0E27;
    --bg-secondary: #141937;
    --bg-tertiary: #1E2547;
    --bg-glass: rgba(255, 255, 255, 0.05);
    
    --text-primary: #FFFFFF;
    --text-secondary: #B8C1EC;
    --text-muted: #7B83A8;
    
    --gradient-primary: linear-gradient(135deg, var(--primary) 0%, #00E676 100%);
    --gradient-secondary: linear-gradient(135deg, var(--secondary) 0%, #FFEA00 100%);
    --gradient-dark: linear-gradient(135deg, #0A0E27 0%, #1E2547 100%);
    
    /* Shadows & Effects */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(0, 200, 83, 0.3);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ==================== Navigation ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(10, 14, 39, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition-base);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 700;
    font-size: 1.25rem;
    transition: var(--transition-fast);
}

.logo-link:hover {
    transform: translateY(-2px);
}

.logo {
    width: 40px;
    height: 40px;
    filter: drop-shadow(0 0 10px rgba(0, 200, 83, 0.5));
}

.logo-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition-fast);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition-base);
}

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

.cta-button {
    background: var(--gradient-primary);
    color: white;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-glow);
}

.cta-button::after {
    display: none;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(0, 200, 83, 0.5);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.mobile-menu-toggle span {
    width: 25px;
    height: 2px;
    background: var(--text-primary);
    transition: var(--transition-base);
}

/* ==================== Hero Section ==================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl) 0;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    inset: 0;
    background: var(--gradient-dark);
    opacity: 0.9;
}

.hero-background::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(0, 200, 83, 0.15) 0%, transparent 70%);
    top: -200px;
    right: -200px;
    animation: float 8s ease-in-out infinite;
}

.hero-background::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(255, 214, 0, 0.1) 0%, transparent 70%);
    bottom: -150px;
    left: -150px;
    animation: float 10s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translate(0, 0) rotate(0deg); }
    50% { transform: translate(30px, 30px) rotate(180deg); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, #FFFFFF 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    font-weight: 300;
    font-style: italic;
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

.hero-features {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.4s backwards;
}

.hero-feature {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    transition: var(--transition-base);
}

.hero-feature:hover {
    background: rgba(0, 200, 83, 0.1);
    border-color: var(--primary);
    transform: translateY(-4px);
}

.feature-icon {
    width: 24px;
    height: 24px;
    color: var(--primary);
}

.hero-badge {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-xl);
    animation: fadeInUp 0.8s ease 0.6s backwards;
}

.hero-badge p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
}

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

/* ==================== Download Section ==================== */
.download-section {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.download-card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: var(--transition-base);
    position: relative;
    overflow: hidden;
}

.download-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-base);
}

.download-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}

.download-card:hover::before {
    opacity: 0.05;
}

.download-card > * {
    position: relative;
    z-index: 1;
}

.card-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
}

.android-card .card-icon {
    background: linear-gradient(135deg, #3DDC84 0%, #00C853 100%);
}

.ios-card .card-icon {
    background: linear-gradient(135deg, #147EFB 0%, #0A5FCC 100%);
}

.card-icon svg {
    width: 48px;
    height: 48px;
    color: white;
}

.download-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.download-card p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
}

.download-button {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--gradient-primary);
    color: white;
    text-decoration: none;
    border-radius: var(--radius-lg);
    font-weight: 600;
    transition: var(--transition-base);
    box-shadow: var(--shadow-md);
}

.download-button:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-glow);
}

/* ==================== Sections ==================== */
.section-title {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    background: linear-gradient(135deg, #FFFFFF 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ==================== How to Use Section ==================== */
.how-to-use {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.steps-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.step-card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    text-align: center;
    transition: var(--transition-base);
}

.step-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
}

.step-number {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-md);
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    font-weight: 800;
    color: white;
    box-shadow: var(--shadow-glow);
}

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

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

.resources {
    text-align: center;
    margin-top: var(--spacing-xl);
}

.resources-intro {
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
}

.resource-links {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.resource-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-base);
}

.resource-link:hover {
    background: var(--gradient-primary);
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.resource-link svg {
    width: 20px;
    height: 20px;
}

/* ==================== Sample Reports Section ==================== */
.samples {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

.samples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

.sample-card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: var(--transition-base);
    position: relative;
    overflow: hidden;
}

.sample-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: var(--transition-base);
}

.sample-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: var(--shadow-md);
}

.sample-card:hover::before {
    opacity: 0.05;
}

.sample-content {
    position: relative;
    z-index: 1;
}

.sample-title {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.sample-meta {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-md);
}

.sample-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.sample-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    background: var(--bg-tertiary);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition-fast);
}

.sample-link.analysis {
    border-color: var(--primary);
}

.sample-link.video {
    border-color: #FF5252;
}

.sample-link:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.sample-link.analysis:hover {
    background: var(--primary);
    color: white;
}

.sample-link.video:hover {
    background: #FF5252;
    color: white;
}

.sample-link svg {
    width: 16px;
    height: 16px;
}

/* ==================== Footer ==================== */
.footer {
    background: var(--bg-tertiary);
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

.footer a {
    color: var(--primary);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

/* ==================== Responsive Design ==================== */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        flex-direction: column;
        background: rgba(10, 14, 39, 0.98);
        backdrop-filter: blur(10px);
        padding: var(--spacing-lg);
        gap: var(--spacing-md);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-base);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .mobile-menu-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .mobile-menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .mobile-menu-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -7px);
    }
    
    .hero-features {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .download-grid,
    .steps-grid {
        grid-template-columns: 1fr;
    }
    
    .samples-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-xl: 2rem;
        --spacing-2xl: 3rem;
    }
    
    .hero {
        min-height: auto;
        padding: 6rem 0 4rem;
    }
    
    .resource-links {
        flex-direction: column;
    }
}