/* Main CSS file for Rifat Erdem Sahin's Personal Website */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-accent: #f1f5f9;
    --border-color: #e5e7eb;
    --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);
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
    align-items: center;
}

.nav-links > li {
    position: relative;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
    display: block;
}

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

/* Dropdown styling */
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background: white;
    min-width: 200px;
    box-shadow: var(--shadow-lg);
    border-radius: 8px;
    padding: 0.5rem 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    list-style: none;
    z-index: 1001;
    border: 1px solid var(--border-color);
}

.nav-links li:hover .dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown-menu li a {
    padding: 0.75rem 1.5rem;
    font-size: 0.9rem;
    white-space: nowrap;
}

.dropdown-menu li a:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
}

/* Secondary/Utility Nav */
.nav-utility {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

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

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

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    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 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content {
    color: white;
}

.hero-greeting {
    font-size: 1.2rem;
    font-weight: 500;
    margin-bottom: 1rem;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero-description {
    font-size: 1.1rem;
    line-height: 1.7;
    margin-bottom: 2.5rem;
    opacity: 0.8;
    animation: fadeInUp 0.8s ease 0.6s both;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    animation: fadeInUp 0.8s ease 0.8s both;
}

.btn {
    padding: 1rem 2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    border: none;
    cursor: pointer;
}

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

.btn-primary:hover {
    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 {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInRight 1s ease 0.5s both;
}

.profile-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 20px;
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow-xl);
}

.profile-avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    border: 3px solid rgba(255, 255, 255, 0.3);
}

.profile-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.profile-info {
    color: white;
}

.profile-name {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.profile-title {
    font-size: 1rem;
    opacity: 0.8;
    margin-bottom: 1rem;
}

.profile-location {
    font-size: 0.9rem;
    opacity: 0.7;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

/* About Section */
.about {
    padding: 6rem 0;
    background: var(--bg-secondary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-primary);
    max-width: 600px;
    margin: 0 auto;
}

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

.about-text {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

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

.about-text p:last-child {
    margin-bottom: 0;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.skill-card {
    background: white;
    padding: 1.5rem;
    border-radius: 15px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

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

.skill-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
    font-size: 1.5rem;
    color: white;
}

.skill-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.skill-description {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

/* CTA Section */
.cta {
    padding: 6rem 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
}

.cta-content {
    max-width: 800px;
    margin: 0 auto;
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
}

.cta-description {
    font-size: 1.2rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
}

.cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Video Section */
.video-section {
    padding: 6rem 0;
    background: var(--bg-primary);
}

.video-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.video-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.video-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.video-container {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    margin-bottom: 2rem;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: var(--shadow-xl);
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.video-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Social Media Section */
.social-section {
    padding: 4rem 0;
    background: var(--bg-secondary);
}

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

.social-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1rem;
}

.social-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    flex-wrap: wrap;
}

.social-link {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    padding: 1.5rem;
    background: white;
    border-radius: 15px;
    box-shadow: var(--shadow-md);
    text-decoration: none;
    transition: all 0.3s ease;
    min-width: 120px;
}

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

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

.social-text {
    font-weight: 600;
    color: var(--text-primary);
}

.social-link.linkedin:hover {
    background: #0077b5;
    color: white;
}

.social-link.linkedin:hover .social-text {
    color: white;
}

.social-link.youtube:hover {
    background: #ff0000;
    color: white;
}

.social-link.youtube:hover .social-text {
    color: white;
}

.social-link.udemy:hover {
    background: #A435F0;
    color: white;
}

.social-link.udemy:hover .social-text {
    color: white;
}

.social-link.coursera:hover {
    background: #0056D3;
    color: white;
}

.social-link.coursera:hover .social-text {
    color: white;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 2rem;
    text-align: center;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.footer-text {
    font-size: 1rem;
    opacity: 0.8;
    margin-bottom: 1rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-links a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 2rem;
    font-size: 0.9rem;
    opacity: 0.6;
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

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

    .hero-cta {
        justify-content: center;
        flex-wrap: wrap;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

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

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

    .footer-links {
        flex-direction: column;
        gap: 1rem;
    }

    .social-links {
        gap: 1rem;
    }

    .social-link {
        min-width: 100px;
        padding: 1rem;
    }

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

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

    .video-cta {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

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

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

    .container {
        padding: 0 1rem;
    }

    .nav-container {
        padding: 0 1rem;
    }
}

/* Scroll animations */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}