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

:root {
    /* Primary Colors */
    --primary-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --secondary-gradient: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --accent-gradient: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    
    /* Neutral Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9ff;
    --bg-tertiary: #f0f2f8;
    --text-primary: #1a1a2e;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    
    /* Accent Colors */
    --purple-500: #667eea;
    --purple-600: #5a67d8;
    --pink-500: #f5576c;
    --blue-500: #4facfe;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* 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: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-secondary);
    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 {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

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

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

.nav-links a:hover {
    color: var(--purple-500);
}

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

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

/* ===== Hero Section ===== */
.hero {
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, #f8f9ff 0%, #fff5f7 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 500px;
    height: 500px;
    background: var(--primary-gradient);
    border-radius: 50%;
    opacity: 0.05;
    filter: blur(80px);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content {
    animation: fadeInUp 0.8s ease;
}

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

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

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

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    max-width: 500px;
}

.cta-button {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    background: var(--primary-gradient);
    color: white;
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1.125rem;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.cta-button:active {
    transform: translateY(0);
}

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

.floating-card {
    position: absolute;
    background: white;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-xl);
    animation: float 3s ease-in-out infinite;
}

.floating-card .image-placeholder {
    font-size: 4rem;
    text-align: center;
}

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

.card-2 {
    top: 40%;
    right: 10%;
    animation-delay: 0.5s;
}

.card-3 {
    bottom: 10%;
    left: 30%;
    animation-delay: 1s;
}

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

/* ===== Sections ===== */
.section {
    padding: var(--spacing-2xl) 0;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--text-primary);
}

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

.step-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    position: relative;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

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

.step-number {
    position: absolute;
    top: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 40px;
    height: 40px;
    background: var(--primary-gradient);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
}

.step-icon {
    font-size: 3rem;
    margin: var(--spacing-md) 0;
}

.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;
}

/* ===== Upload Section ===== */
.upload-section {
    background: white;
}

.upload-container {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
    align-items: center;
}

.upload-box {
    position: relative;
}

.upload-label {
    display: block;
    border: 3px dashed #d1d5db;
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    background: var(--bg-secondary);
    min-height: 300px;
    position: relative;
    overflow: hidden;
}

.upload-label:hover {
    border-color: var(--purple-500);
    background: #fafaff;
}

.upload-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-secondary);
}

.upload-content svg {
    color: var(--purple-500);
}

.upload-content h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-top: var(--spacing-sm);
}

.upload-content p {
    font-size: 0.95rem;
}

.file-info {
    font-size: 0.85rem;
    color: var(--text-light);
}

.preview-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: var(--radius-md);
    position: absolute;
    top: 0;
    left: 0;
}

.remove-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    z-index: 10;
}

.remove-btn:hover {
    background: rgba(0, 0, 0, 0.9);
    transform: scale(1.1);
}

.plus-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--purple-500);
}

/* ===== Pose Selection ===== */
.pose-selection {
    margin-top: var(--spacing-xl);
}

.pose-title {
    font-size: 1.5rem;
    font-weight: 600;
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.pose-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: var(--spacing-md);
}

.pose-card {
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.pose-card:hover {
    background: white;
    border-color: var(--purple-500);
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.pose-card.selected {
    background: linear-gradient(white, white) padding-box,
                var(--primary-gradient) border-box;
    border: 2px solid transparent;
    box-shadow: var(--shadow-lg);
}

.pose-emoji {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-xs);
}

.pose-card h4 {
    font-size: 1rem;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.pose-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* ===== Generate Button ===== */
.generate-section {
    display: flex;
    justify-content: center;
    margin-top: var(--spacing-xl);
}

.generate-button {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 1.25rem 2.5rem;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1.25rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
}

.generate-button:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

.generate-button:active {
    transform: translateY(0);
}

.generate-button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* ===== Loading State ===== */
.loading-container {
    text-align: center;
    padding: var(--spacing-xl);
    background: white;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    margin-top: var(--spacing-xl);
}

.loading-spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto var(--spacing-md);
    border: 4px solid var(--bg-tertiary);
    border-top: 4px solid var(--purple-500);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.loading-container h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

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

.progress-bar {
    width: 100%;
    max-width: 400px;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: 999px;
    margin: 0 auto;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary-gradient);
    border-radius: 999px;
    animation: progress 2s ease-in-out infinite;
}

@keyframes progress {
    0% { width: 0%; }
    50% { width: 70%; }
    100% { width: 100%; }
}

/* ===== Result Section ===== */
.result-section {
    margin-top: var(--spacing-xl);
}

.result-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    text-align: center;
}

.result-card h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.result-image-container {
    margin-bottom: var(--spacing-lg);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.result-image {
    width: 100%;
    max-width: 600px;
    height: auto;
    display: block;
    margin: 0 auto;
}

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

.download-button {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    background: var(--primary-gradient);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
}

.download-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.secondary-button {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 1rem 2rem;
    background: white;
    color: var(--purple-500);
    border: 2px solid var(--purple-500);
    border-radius: var(--radius-md);
    font-size: 1.125rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
}

.secondary-button:hover {
    background: var(--bg-secondary);
    transform: translateY(-2px);
}

/* ===== Features Section ===== */
.features-section {
    background: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.feature-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

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

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

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

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

/* ===== Use Cases Section ===== */
.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.use-case-card {
    background: linear-gradient(135deg, #667eea15 0%, #764ba215 100%);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid rgba(102, 126, 234, 0.1);
    transition: all var(--transition-base);
}

.use-case-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--purple-500);
}

.use-case-emoji {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-md);
}

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

.use-case-card p {
    color: var(--text-secondary);
}

/* ===== Footer ===== */
.footer {
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

.footer-brand .logo {
    color: white;
    margin-bottom: var(--spacing-md);
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.7);
}

.footer-links {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: flex-end;
}

.footer-column h4 {
    margin-bottom: var(--spacing-md);
    font-size: 1.125rem;
}

.footer-column a {
    display: block;
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    margin-bottom: var(--spacing-xs);
    transition: color var(--transition-fast);
}

.footer-column a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-md);
    text-align: center;
    color: rgba(255, 255, 255, 0.6);
}

/* ===== Responsive Design ===== */
@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
    }
    
    .hero-visual {
        display: none;
    }
}

@media (max-width: 768px) {
    .upload-container {
        grid-template-columns: 1fr;
    }
    
    .plus-icon {
        transform: rotate(90deg);
    }
    
    .pose-grid {
        grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    }
    
    .nav-links {
        gap: var(--spacing-md);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        justify-content: flex-start;
    }
    
    .result-actions {
        flex-direction: column;
    }
    
    .download-button,
    .secondary-button {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .upload-label {
        padding: var(--spacing-lg);
        min-height: 250px;
    }
    
    .pose-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .steps-grid {
        grid-template-columns: 1fr;
    }
}

/* ===== Utility Classes ===== */
.hidden {
    display: none !important;
}

.fade-in {
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.slide-up {
    animation: slideUp 0.5s ease;
}

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