/* ========================================
   CSS Custom Properties (Design Tokens)
   ======================================== */
:root {
    /* Color Palette */
    --color-black: #000000;
    --color-white: #FFFFFF;
    --color-gray-dark: #343a40;
    --color-gray-medium: #6c757d;
    --color-gray-light: #adb5bd;
    --color-gray-lighter: #dee2e6;
    --color-gray-bg: #f8f9fa;
    
    /* Typography */
    --font-heading: 'Saira Extra Condensed', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-body: 'Open Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Layout */
    --sidebar-width: 280px;
    --content-max-width: 900px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.2);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-gray-dark);
    background-color: var(--color-white);
    overflow-x: hidden;
}

/* ========================================
   Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-gray-dark);
}

h1 {
    font-size: 4rem;
    margin-bottom: var(--spacing-md);
}

h2 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-sm);
}

p {
    margin-bottom: var(--spacing-md);
}

/* ========================================
   Sidebar Navigation
   ======================================== */
.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--color-black);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    transition: transform var(--transition-normal);
}

.sidebar-content {
    text-align: center;
    padding: var(--spacing-lg);
}

.profile-section {
    margin-bottom: var(--spacing-xl);
}

.profile-img {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid var(--color-white);
    box-shadow: var(--shadow-lg);
    transition: transform var(--transition-normal);
}

.profile-img:hover {
    transform: scale(1.05);
}

/* Social Icons */
.social-icons {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-sm);
}

.social-icon {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-white);
    font-size: 1.25rem;
    text-decoration: none;
    transition: all var(--transition-fast);
    border: 2px solid transparent;
}

.social-icon:hover {
    background-color: var(--color-white);
    color: var(--color-black);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

/* ========================================
   Main Content Area
   ======================================== */
.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    padding: var(--spacing-xxl) var(--spacing-xl);
    background-color: var(--color-white);
}

.content-wrapper {
    max-width: var(--content-max-width);
    margin: 0 auto;
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    padding: var(--spacing-xxl) 0;
    text-align: left;
}

.name {
    font-size: 5rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-md);
    line-height: 1;
}

.first-name {
    color: var(--color-gray-dark);
    font-weight: 700;
}

.last-name {
    color: var(--color-gray-medium);
    font-weight: 500;
}

.title-bar {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    font-family: var(--font-heading);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-gray-medium);
}

.separator {
    color: var(--color-gray-light);
}

.description {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--color-gray-medium);
    margin-bottom: var(--spacing-xl);
    max-width: 700px;
}

/* ========================================
   Buttons
   ======================================== */
.cta-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    font-family: var(--font-heading);
    font-size: 0.95rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    text-decoration: none;
    border-radius: 4px;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background-color: var(--color-white);
    color: var(--color-black);
    border-color: var(--color-black);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--color-white);
    color: var(--color-black);
    border-color: var(--color-gray-light);
}

.btn-secondary:hover {
    background-color: var(--color-black);
    color: var(--color-white);
    border-color: var(--color-black);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ========================================
   Content Sections
   ======================================== */
.about, .skills {
    padding: var(--spacing-xxl) 0;
    border-top: 1px solid var(--color-gray-lighter);
}

.about p {
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--color-gray-medium);
}

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

.skill-item {
    padding: var(--spacing-lg);
    background-color: var(--color-gray-bg);
    border-radius: 8px;
    text-align: center;
    transition: all var(--transition-normal);
}

.skill-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    background-color: var(--color-white);
    border: 1px solid var(--color-gray-lighter);
}

.skill-item i {
    font-size: 2.5rem;
    color: var(--color-black);
    margin-bottom: var(--spacing-md);
}

.skill-item h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.skill-item p {
    font-size: 0.95rem;
    color: var(--color-gray-medium);
    margin-bottom: 0;
}

/* ========================================
   Footer
   ======================================== */
.footer {
    padding: var(--spacing-xl) 0;
    text-align: center;
    color: var(--color-gray-medium);
    font-size: 0.9rem;
    border-top: 1px solid var(--color-gray-lighter);
    margin-top: var(--spacing-xxl);
}

/* ========================================
   Mobile Menu Toggle
   ======================================== */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: var(--spacing-md);
    left: var(--spacing-md);
    width: 50px;
    height: 50px;
    background-color: var(--color-black);
    color: var(--color-white);
    border: none;
    border-radius: 8px;
    font-size: 1.5rem;
    cursor: pointer;
    z-index: 1001;
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-md);
}

.mobile-menu-toggle:hover {
    background-color: var(--color-gray-dark);
    transform: scale(1.05);
}

.mobile-menu-toggle.active {
    background-color: var(--color-white);
    color: var(--color-black);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 992px) {
    :root {
        --sidebar-width: 240px;
    }
    
    .name {
        font-size: 4rem;
    }
    
    h2 {
        font-size: 2rem;
    }
}

@media (max-width: 768px) {
    .sidebar {
        transform: translateX(-100%);
        width: 280px;
    }
    
    .sidebar.active {
        transform: translateX(0);
        box-shadow: var(--shadow-lg);
    }
    
    .main-content {
        margin-left: 0;
        padding: var(--spacing-xl) var(--spacing-md);
    }
    
    .mobile-menu-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    .name {
        font-size: 3rem;
    }
    
    .hero {
        padding: var(--spacing-xl) 0;
    }
    
    .profile-img {
        width: 150px;
        height: 150px;
    }
    
    .cta-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .name {
        font-size: 2.5rem;
    }
    
    h2 {
        font-size: 1.75rem;
    }
    
    .title-bar {
        font-size: 0.8rem;
    }
    
    .description {
        font-size: 1rem;
    }
    
    .profile-img {
        width: 120px;
        height: 120px;
    }
    
    .social-icon {
        width: 42px;
        height: 42px;
        font-size: 1.1rem;
    }
}

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

.hero, .about, .skills {
    animation: fadeInUp var(--transition-slow) ease-out;
}

/* ========================================
   Signature Project
   ======================================== */
.signature-project {
    margin-top: var(--spacing-md);
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, #000000 0%, #1a1a1a 100%);
    color: var(--color-white);
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    position: relative;
    overflow: hidden;
}

.signature-project::before {
    content: "🌟 İMZA PROJE";
    position: absolute;
    top: 25px;
    right: -45px;
    background: #ffd700;
    color: #000;
    padding: 8px 50px;
    font-size: 0.85rem;
    font-weight: 800;
    transform: rotate(45deg);
    z-index: 1;
    letter-spacing: 1px;
}

.signature-header h3 {
    color: var(--color-white);
    font-size: 2.2rem;
    margin-bottom: var(--spacing-xs);
}

.signature-tech {
    display: flex;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-sm);
}

.tech-badge {
    background: rgba(255,255,255,0.15);
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.85rem;
    font-weight: 600;
    color: #e0e0e0;
}

.signature-desc p {
    color: rgba(255,255,255,0.85);
    font-size: 1.1rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-sm);
}

.signature-innovation {
    background: rgba(255, 215, 0, 0.1);
    border-left: 4px solid #ffd700;
    padding: var(--spacing-md);
    border-radius: 0 8px 8px 0;
    margin-bottom: var(--spacing-md);
}

.signature-innovation h4 {
    color: #ffd700;
    margin-bottom: 8px;
    font-size: 1.15rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.signature-innovation p {
    margin-bottom: 0;
    color: rgba(255,255,255,0.9);
    font-size: 0.95rem;
    line-height: 1.6;
}

.signature-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-xs);
}

.signature-links a {
    color: var(--color-white);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    background: rgba(255,255,255,0.15);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.signature-links a:hover {
    background: rgba(255,255,255,0.25);
    transform: translateY(-3px);
}

@media (max-width: 768px) {
    .signature-project::before {
        top: 20px;
        right: -55px;
        font-size: 0.7rem;
    }
    .signature-header h3 {
        font-size: 1.8rem;
    }
}

/* Smooth scroll offset for fixed sidebar */
html {
    scroll-padding-top: var(--spacing-xl);
}