/* ===========================
   CSS Variables & Root Styles
   =========================== */
:root {
    /* Light Mode Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #e9ecef;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --text-light: #adb5bd;
    --accent-primary: #4f46e5;
    --accent-secondary: #7c3aed;
    --accent-hover: #4338ca;
    --border-color: #dee2e6;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.15);
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Typography */
    --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
}

/* Dark Mode Colors */
[data-theme="dark"] {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --text-primary: #eee;
    --text-secondary: #b8b8b8;
    --text-light: #888;
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-hover: #5b5fd8;
    --border-color: #2d3748;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.5);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color var(--transition-base), color var(--transition-base);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

ul {
    list-style: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ===========================
   Container & Layout
   =========================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===========================
   Navigation Bar
   =========================== */
.navbar {
    background-color: var(--bg-primary);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: background-color var(--transition-base);
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--accent-primary);
    cursor: pointer;
}

.logo i {
    font-size: 1.5rem;
}

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

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-links a:hover {
    color: var(--accent-primary);
    background-color: var(--bg-secondary);
}

.nav-links a.active {
    color: var(--accent-primary);
    font-weight: 600;
}

.nav-links a.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: var(--spacing-sm);
    right: var(--spacing-sm);
    height: 2px;
    background: var(--accent-primary);
}

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

.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--accent-primary);
    color: white;
    transform: rotate(20deg);
}

.mobile-menu-toggle {
    display: none;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    background: var(--gradient-primary);
    color: white;
    padding: var(--spacing-2xl) 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 1440 320"><path fill="rgba(255,255,255,0.1)" d="M0,96L48,112C96,128,192,160,288,160C384,160,480,128,576,112C672,96,768,96,864,112C960,128,1056,160,1152,160C1248,160,1344,128,1392,112L1440,96L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>') no-repeat bottom;
    background-size: cover;
    opacity: 0.3;
}

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

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-lg);
    opacity: 0.95;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

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

.hero-features {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.6s backwards;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-base);
}

.feature-item i {
    font-size: 1.25rem;
}

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-lg);
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-fast);
    cursor: pointer;
}

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

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

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 2px solid white;
}

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

.btn-small {
    padding: 0.5rem 1rem;
    font-size: var(--font-size-sm);
}

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

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

.section-subtitle {
    text-align: center;
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

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

.tool-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-primary);
}

.tool-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
    color: white;
}

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

.tool-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-size: var(--font-size-sm);
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
}

.upload-area:hover {
    border-color: var(--accent-primary);
    background-color: var(--bg-secondary);
}

.upload-area.drag-over {
    border-color: var(--accent-primary);
    background-color: var(--accent-primary);
    color: white;
}

.upload-area.drag-over i {
    color: white;
}

.upload-area i {
    font-size: 2.5rem;
    color: var(--accent-primary);
    margin-bottom: var(--spacing-sm);
    display: block;
}

.upload-area p {
    color: var(--text-secondary);
    font-size: var(--font-size-sm);
}

.file-input {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
}

.preview-area {
    text-align: center;
}

.preview-image {
    max-width: 100%;
    max-height: 300px;
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
    box-shadow: var(--shadow-md);
}

.preview-actions {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
}

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

.btn-convert:hover {
    opacity: 0.9;
    transform: translateY(-2px);
}

.btn-reset {
    background-color: var(--bg-secondary);
    color: var(--text-primary);
}

.btn-reset:hover {
    background-color: var(--bg-tertiary);
}

/* ===========================
   FAQ Section
   =========================== */
.faq-section {
    padding: var(--spacing-2xl) 0;
    background-color: var(--bg-primary);
}

.faq-grid {
    display: grid;
    gap: var(--spacing-md);
    max-width: 900px;
    margin: 0 auto;
}

.faq-item {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-base);
}

.faq-question {
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.faq-question h3 {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
}

.faq-question i {
    color: var(--accent-primary);
    transition: transform var(--transition-base);
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-base);
}

.faq-answer p {
    padding: 0 var(--spacing-md) var(--spacing-md);
    color: var(--text-secondary);
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

/* ===========================
   Footer
   =========================== */
.footer {
    background-color: var(--bg-secondary);
    padding: var(--spacing-2xl) 0 var(--spacing-md);
    margin-top: var(--spacing-2xl);
}

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

.footer-col h4 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--accent-primary);
    margin-bottom: var(--spacing-md);
}

.footer-logo i {
    font-size: 1.5rem;
}

.footer-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

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

.social-links a {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-full);
    background-color: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.social-links a:hover {
    background-color: var(--accent-primary);
    color: white;
    transform: translateY(-3px);
}

.footer-links li {
    margin-bottom: var(--spacing-xs);
}

.footer-links a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

.newsletter-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.newsletter-form input {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    transition: border-color var(--transition-fast);
}

.newsletter-form input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.newsletter-form .btn {
    background: var(--gradient-primary);
    color: white;
    border: none;
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
}

/* ===========================
   Page Header
   =========================== */
.page-header {
    background: var(--gradient-primary);
    color: white;
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.page-header h1 {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    margin-bottom: var(--spacing-sm);
}

.page-header p {
    font-size: var(--font-size-lg);
    opacity: 0.95;
}

.last-updated {
    margin-top: var(--spacing-sm);
    font-size: var(--font-size-sm);
    opacity: 0.9;
}

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

.content-wrapper {
    max-width: 900px;
    margin: 0 auto;
}

.content-wrapper h2 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.content-wrapper h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.content-wrapper p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.8;
}

.styled-list {
    margin: var(--spacing-md) 0;
    padding-left: var(--spacing-lg);
}

.styled-list li {
    list-style: disc;
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
    line-height: 1.8;
}

.styled-list li strong {
    color: var(--text-primary);
}

.feature-highlights {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin: var(--spacing-xl) 0;
}

.highlight-card {
    background-color: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    transition: all var(--transition-base);
}

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

.highlight-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
    font-size: 1.5rem;
    color: white;
}

.highlight-card h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-sm);
}

.highlight-card p {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.cta-box {
    background: var(--gradient-primary);
    color: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    text-align: center;
    margin: var(--spacing-2xl) 0;
}

.cta-box h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
    color: white;
}

.cta-box p {
    margin-bottom: var(--spacing-md);
    color: white;
    opacity: 0.95;
}

/* ===========================
   Contact Page
   =========================== */
.contact-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.contact-form-container,
.contact-info-container {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
}

.contact-form {
    margin-top: var(--spacing-lg);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

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

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: border-color var(--transition-fast);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.form-group textarea {
    resize: vertical;
}

.form-success {
    background-color: #d4edda;
    color: #155724;
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    text-align: center;
    margin-top: var(--spacing-md);
}

.form-success i {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
    display: block;
}

.contact-info-items {
    margin-top: var(--spacing-lg);
}

.contact-info-item {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.contact-icon {
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.contact-details h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.contact-details p {
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.social-contact {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

.social-links.large a {
    width: 50px;
    height: 50px;
    font-size: 1.25rem;
}

.contact-faq {
    margin-top: var(--spacing-lg);
}

.faq-simple-item {
    background-color: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
}

.faq-simple-item h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.faq-simple-item i {
    color: var(--accent-primary);
}

.faq-simple-item p {
    color: var(--text-secondary);
    margin: 0;
}

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

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

/* ===========================
   Responsive Design
   =========================== */

/* Tablet */
@media (max-width: 992px) {
    .hero-title {
        font-size: var(--font-size-3xl);
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .contact-layout {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Mobile */
@media (max-width: 768px) {
    .nav-links {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background-color: var(--bg-primary);
        flex-direction: column;
        padding: var(--spacing-xl);
        gap: var(--spacing-md);
        transition: left var(--transition-base);
        box-shadow: var(--shadow-lg);
        align-items: flex-start;
    }
    
    .nav-links.active {
        left: 0;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: var(--font-size-2xl);
    }
    
    .hero-subtitle {
        font-size: var(--font-size-base);
    }
    
    .hero-features {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .tools-grid {
        grid-template-columns: 1fr;
    }
    
    .section-title {
        font-size: var(--font-size-2xl);
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .content-wrapper h2 {
        font-size: var(--font-size-xl);
    }
}

/* Small Mobile */
@media (max-width: 480px) {
    :root {
        --spacing-xl: 2rem;
        --spacing-2xl: 3rem;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-title {
        font-size: var(--font-size-xl);
    }
    
    .tool-card {
        padding: var(--spacing-md);
    }
}

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

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }