/* CSS Variables for Light/Dark Mode */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-card: #ffffff;
    --text-primary: #212529;
    --text-secondary: #6c757d;
    --accent: #007bff;
    --accent-hover: #0056b3;
    --border: #dee2e6;
    --shadow: rgba(0, 0, 0, 0.1);
    --nav-bg: rgba(255, 255, 255, 0.95);
    --hero-bg: linear-gradient(135deg, #007bff 0%, #00d4ff 100%);
    --hero-text: #ffffff;
}

[data-theme="dark"] {
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --bg-card: #252525;
    --text-primary: #ffffff;
    --text-secondary: #b0b0b0;
    --accent: #4fc3f7;
    --accent-hover: #29b6f6;
    --border: #404040;
    --shadow: rgba(0, 0, 0, 0.3);
    --nav-bg: rgba(18, 18, 18, 0.95);
    --hero-bg: linear-gradient(135deg, #4fc3f7 0%, #00b0ff 100%);
    --hero-text: #ffffff;
}

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

html {
    scroll-behavior: smooth;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 16px;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--nav-bg);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 1000;
    box-shadow: 0 2px 10px var(--shadow);
    transition: background 0.3s;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    transition: color 0.3s;
}

.nav-links {
    display: flex;
    list-style: none;
    align-items: center;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--accent);
}

.theme-toggle {
    background: none;
    border: 2px solid var(--border);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 1.2rem;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

/* Main Content */
main {
    padding-top: 80px;
    min-height: calc(100vh - 200px);
}

/* Hero Section */
.hero {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6rem 2rem;
    background: var(--hero-bg);
    color: var(--hero-text);
    position: relative;
    overflow: hidden;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    z-index: 1;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease-out;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    animation: fadeInUp 1.2s ease-out;
}

/* Buttons */
.btn {
    padding: 0.8rem 1.8rem;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-block;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
}

.btn-secondary {
    background: transparent;
    color: var(--hero-text);
    border: 2px solid var(--hero-text);
}

.btn-secondary:hover {
    background: var(--hero-text);
    color: var(--accent);
}

/* Hero Animations */
.hero-animations {
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    pointer-events: none;
}

.floating-shape {
    position: absolute;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.shape-1 {
    width: 100px;
    height: 100px;
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.shape-2 {
    width: 150px;
    height: 150px;
    top: 60%;
    right: 15%;
    animation-delay: 2s;
}

.shape-3 {
    width: 80px;
    height: 80px;
    bottom: 20%;
    left: 20%;
    animation-delay: 4s;
}

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

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

/* Preview Section */
.preview {
    padding: 5rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.preview h2 {
    font-size: 2rem;
    text-align: center;
    margin-bottom: 3rem;
}

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

.preview-card {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
}

.preview-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px var(--shadow);
}

.preview-card h3 {
    color: var(--accent);
    margin-bottom: 1rem;
}

/* About Page */
.about {
    padding: 5rem 2rem;
    max-width: 1000px;
    margin: 0 auto;
}

.about h1 {
    font-size: 3rem;
    margin-bottom: 2rem;
}

.about-text p {
    margin-bottom: 1.5rem;
    font-size: 1.1rem;
}

.skills {
    margin-top: 3rem;
}

.skills h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
}

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

.skill-item {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--shadow);
}

.skill-item h3 {
    color: var(--accent);
    margin-bottom: 1rem;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background: var(--bg-secondary);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    transition: background 0.3s;
}

.tag:hover {
    background: var(--accent);
    color: white;
}

/* Projects Page */
.projects {
    padding: 5rem 2rem;
    max-width: 1400px;
    margin: 0 auto;
}

.projects h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    text-align: center;
}

.projects > p {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-secondary);
}

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

.project-card {
    background: var(--bg-card);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 4px 15px var(--shadow);
    transition: transform 0.3s, box-shadow 0.3s;
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 30px var(--shadow);
}

.project-image {
    height: 200px;
    background: var(--bg-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    font-size: 4rem;
}

.project-content {
    padding: 1.5rem;
}

.project-content h2 {
    margin-bottom: 0.5rem;
}

.project-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.tech-badge {
    background: var(--bg-secondary);
    padding: 0.3rem 0.8rem;
    border-radius: 15px;
    font-size: 0.85rem;
    color: var(--accent);
}

.project-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s;
}

.project-link:hover {
    color: var(--accent-hover);
}

/* Contact Page */
.contact {
    padding: 5rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.contact-info h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.contact-info > p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.contact-icon {
    font-size: 2rem;
}

.contact-text h3 {
    font-size: 1rem;
    color: var(--text-secondary);
}

.contact-text p {
    font-size: 1.2rem;
    font-weight: 600;
}

/* Contact Form */
.contact-form-wrapper {
    background: var(--bg-card);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--shadow);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: 600;
    font-size: 0.9rem;
}

.required {
    color: #dc3545;
}

.form-group input,
.form-group textarea {
    padding: 0.8rem;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    font-family: inherit;
    transition: border-color 0.3s;
    background: var(--bg-primary);
    color: var(--text-primary);
}

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

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-group input.invalid,
.form-group textarea.invalid {
    border-color: #dc3545;
}

.error-message {
    color: #dc3545;
    font-size: 0.85rem;
    min-height: 1.2rem;
}

/* Form Success */
.form-success {
    text-align: center;
    padding: 3rem 2rem;
}

.success-icon {
    font-size: 4rem;
    color: #28a745;
    margin-bottom: 1rem;
}

.form-success h3 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.form-success p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    margin-top: 4rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .navbar {
        padding: 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .nav-links a {
        font-size: 0.9rem;
    }

    .hero {
        padding: 3rem 1rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .about h1,
    .projects h1,
    .contact-info h1 {
        font-size: 2rem;
    }

    .contact-container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .preview-cards {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }
}