/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --dark-color: #1f2937;
    --light-color: #f8fafc;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --border-radius: 0.5rem;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--light-color);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-logo i {
    font-size: 1.8rem;
}

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

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

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

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary-color);
    border-radius: 1px;
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    margin: 3px 0;
    transition: var(--transition);
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    overflow: hidden;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1.5rem;
}

.gradient-text {
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

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

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

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

/* Hero Visual */
.hero-visual {
    position: relative;
    height: 400px;
}

.floating-cards {
    position: relative;
    height: 100%;
}

.card {
    position: absolute;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    animation: float 6s ease-in-out infinite;
}

.card i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.card-1 {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.card-2 {
    top: 50%;
    right: 20%;
    animation-delay: 2s;
}

.card-3 {
    bottom: 20%;
    left: 30%;
    animation-delay: 4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* Features Section */
.features {
    padding: 80px 0;
    background: white;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

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

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

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: white;
    font-size: 2rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.feature-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Prediction Section */
.prediction-section {
    padding: 80px 0;
    background: var(--light-color);
}

.prediction-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    max-width: 1400px;
    margin: 0 auto;
}

.form-container {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.form-tabs {
    display: flex;
    border-bottom: 1px solid var(--border-color);
}

.tab-btn {
    flex: 1;
    padding: 1rem;
    border: none;
    background: var(--light-color);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    font-weight: 500;
}

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

.tab-btn:hover:not(.active) {
    background: var(--border-color);
}

.tab-content {
    display: none;
    padding: 2rem;
}

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

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.input-help {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.form-actions {
    display: flex;
    gap: 1rem;
    justify-content: flex-end;
    padding: 2rem;
    border-top: 1px solid var(--border-color);
    background: var(--light-color);
}

/* Results Container */
.results-container {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    border: 2px dashed #e2e8f0;
    padding: 1rem;
    border-radius: var(--border-radius);
    min-height: 200px;
}

.prediction-result {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    padding: 2rem;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.result-header h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.result-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    color: white;
    background: var(--primary-color);
}

.result-content {
    text-align: center;
}

.result-message {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

.churn-probability {
    font-size: 3rem;
    font-weight: 700;
    margin: 1rem 0;
}

.probability-high {
    color: var(--error-color);
}

.probability-medium {
    color: var(--warning-color);
}

.probability-low {
    color: var(--success-color);
}

.risk-status {
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-weight: 600;
    display: inline-block;
    margin-top: 1rem;
}

.risk-high {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
}

.risk-medium {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

.risk-low {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
}

.risk-factors,
.recommendations {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    padding: 1.5rem;
}

.risk-factors h4,
.recommendations h4 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.factors-list,
.recommendations-list {
    list-style: none;
}

.factor-item,
.recommendation-item {
    padding: 0.75rem;
    margin-bottom: 0.5rem;
    background: var(--light-color);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary-color);
}

.factor-item i,
.recommendation-item i {
    margin-right: 0.5rem;
    color: var(--primary-color);
}

/* Analytics Section */
.analytics-section {
    padding: 80px 0;
    background: white;
}

/* Prediction Summary Widget */
.prediction-summary {
    margin-bottom: 3rem;
}

.summary-card {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-lg);
}

.summary-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    text-align: center;
}

.summary-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.summary-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.summary-label {
    font-size: 0.9rem;
    opacity: 0.8;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.summary-value {
    font-size: 1.25rem;
    font-weight: 600;
}

.analytics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.chart-container {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    padding: 1.5rem;
}

.chart-container h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.chart-container canvas {
    width: 100% !important;
    height: 250px !important;
}

/* About Section */
.about-section {
    padding: 80px 0;
    background: var(--light-color);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about-text h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.about-text p {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    line-height: 1.7;
}

.stats {
    display: flex;
    gap: 2rem;
}

.stat {
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.tech-stack {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.tech-item {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: var(--transition);
}

.tech-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.tech-item i {
    font-size: 2rem;
    color: var(--primary-color);
}

.tech-item span {
    font-weight: 600;
    color: var(--text-primary);
}

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

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

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-logo i {
    color: var(--primary-color);
}

.footer-section h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

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

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

.footer-section ul li a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: var(--transition);
}

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

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    text-decoration: none;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 1rem;
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
}

/* Loading Spinner */
.loading-spinner {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: none;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    z-index: 9999;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-spinner p {
    color: white;
    font-size: 1.1rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .prediction-container {
        grid-template-columns: 1fr;
    }
    
    .about-content {
        grid-template-columns: 1fr;
    }
    
    .stats {
        justify-content: center;
    }
    
    .form-tabs {
        flex-direction: column;
    }
    
    .form-actions {
        flex-direction: column;
    }
    
    .hero-buttons {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .analytics-grid {
        grid-template-columns: 1fr;
    }
    
    .tech-stack {
        grid-template-columns: 1fr;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

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

::-webkit-scrollbar-track {
    background: var(--light-color);
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* Error states for form validation */
.form-group input.error,
.form-group select.error {
    border-color: var(--error-color);
    box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.1);
}

.notification {
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}