/* CSS Reset & Variable overrides for clean human designer light aesthetic */
        :root {
            --bg-color: #ffffff;
            --bg-section: #f8fafc;
            --bg-card: #ffffff;
            --bg-card-hover: #f1f5f9;
            --border-color: #e2e8f0;
            --text-heading: #0f172a;
            --text-body: #334155;
            --text-muted: #64748b;
            --primary: #2563eb;
            --primary-hover: #1d4ed8;
            --secondary: #0f172a;
            --secondary-hover: #1e293b;
            --transition-speed: 0.25s;
            --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
            --container-max-width: 1140px;
        }

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

        body {
            font-family: var(--font-stack);
            background-color: var(--bg-color);
            color: var(--text-body);
            line-height: 1.6;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
        }

        /* Container utility */
        .container {
            width: 100%;
            max-width: var(--container-max-width);
            margin: 0 auto;
            padding: 0 1.5rem;
        }

        /* Typography & Custom Headings */
        h1, h2, h3, h4 {
            color: var(--text-heading);
            font-weight: 700;
            line-height: 1.25;
            letter-spacing: -0.02em;
        }

        h1 {
            font-size: clamp(2.25rem, 5vw, 3.05rem);
            margin-bottom: 1.25rem;
        }

        h2 {
            font-size: clamp(1.75rem, 4vw, 2.25rem);
            text-align: center;
            margin-bottom: 1rem;
        }

        h2::after {
            content: '';
            display: block;
            width: 45px;
            height: 3px;
            background-color: var(--primary);
            margin: 0.75rem auto 0 auto;
            border-radius: 2px;
        }

        h3 {
            font-size: 1.2rem;
            margin-bottom: 0.5rem;
            font-weight: 600;
        }

        p {
            color: var(--text-body);
            font-size: 1rem;
        }

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

        button, input, textarea {
            font-family: inherit;
            font-size: 1rem;
        }

        /* Accessibility: Skip to Content */
        .skip-link {
            position: absolute;
            top: -100px;
            left: 0;
            background: var(--primary);
            color: #ffffff;
            padding: 1rem;
            z-index: 1000;
            transition: top 0.2s;
        }
        .skip-link:focus {
            top: 0;
        }

        /* Focus styles for Keyboard navigation */
        a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible {
            outline: 2px solid var(--primary);
            outline-offset: 4px;
        }

        /* Header Section */
        header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background-color: rgba(255, 255, 255, 0.95);
            backdrop-filter: blur(8px);
            -webkit-backdrop-filter: blur(8px);
            border-bottom: 1px solid var(--border-color);
            z-index: 900;
            transition: all var(--transition-speed);
        }

        .header-wrap {
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 75px;
        }

        /* Logo design */
        .logo {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            font-weight: 700;
            font-size: 1.25rem;
            color: var(--text-heading);
            letter-spacing: -0.03em;
        }

        .logo svg {
            width: 32px;
            height: 32px;
        }

        /* Desktop Nav */
        nav {
            display: flex;
            align-items: center;
            gap: 2rem;
        }

        .nav-links {
            display: flex;
            gap: 1.75rem;
            list-style: none;
        }

        .nav-links a {
            font-weight: 500;
            font-size: 0.9rem;
            color: var(--text-body);
            padding: 0.5rem 0;
            position: relative;
        }

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

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

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

        /* Nav Contact Button */
        .btn-header {
            background-color: transparent;
            border: 1px solid var(--border-color);
            padding: 0.5rem 1.1rem;
            border-radius: 6px;
            color: var(--text-heading);
            font-weight: 600;
            font-size: 0.85rem;
            display: inline-flex;
            align-items: center;
            gap: 0.5rem;
            cursor: pointer;
            transition: background var(--transition-speed), border-color var(--transition-speed), color var(--transition-speed);
        }

        .btn-header:hover {
            background-color: var(--primary);
            border-color: var(--primary);
            color: #ffffff;
        }

        /* Mobile Menu Toggle */
        .menu-toggle {
            display: none;
            background: none;
            border: none;
            cursor: pointer;
            color: var(--text-heading);
            padding: 0.5rem;
            z-index: 1001;
            aria-label: "Menüyü Aç/Kapat";
        }

        .menu-toggle svg {
            width: 24px;
            height: 24px;
            fill: none;
            stroke: currentColor;
            stroke-width: 2.5;
            stroke-linecap: round;
        }

        /* Hero Section */
        .hero {
            padding: 150px 0 80px 0;
            min-height: 85vh;
            display: flex;
            align-items: center;
            background-color: #ffffff;
            position: relative;
        }

        .hero-grid {
            display: grid;
            grid-template-columns: 1.05fr 0.95fr;
            align-items: center;
            position: relative;
            z-index: 2;
        }

        .hero-content {
            max-width: 600px;
        }

        .hero-badge {
            background-color: var(--bg-section);
            border: 1px solid var(--border-color);
            color: var(--text-body);
            padding: 0.35rem 0.85rem;
            border-radius: 4px;
            font-size: 0.8rem;
            font-weight: 600;
            display: inline-flex;
            align-items: center;
            gap: 0.4rem;
            margin-bottom: 1.25rem;
            letter-spacing: 0.02em;
        }

        .hero-badge svg {
            color: var(--primary);
        }

        .hero-desc {
            font-size: 1.05rem;
            color: var(--text-body);
            margin-bottom: 2rem;
            line-height: 1.7;
        }

        .hero-ctas {
            display: flex;
            flex-wrap: wrap;
            gap: 1rem;
        }

        /* Custom buttons styling */
        .btn {
            padding: 0.8rem 1.75rem;
            border-radius: 6px;
            font-weight: 600;
            font-size: 0.95rem;
            cursor: pointer;
            transition: background-color var(--transition-speed), color var(--transition-speed), border-color var(--transition-speed);
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            border: none;
        }

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

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

        .btn-secondary {
            background-color: transparent;
            border: 1px solid var(--border-color);
            color: var(--text-body);
        }

        .btn-secondary:hover {
            background-color: var(--bg-section);
            border-color: #cbd5e1;
            color: var(--text-heading);
        }

        /* Hero Graphic */
        .hero-visual {
            display: flex;
            justify-content: center;
            position: relative;
        }

        .visual-container {
            width: 100%;
            position: relative;
        }

        .visual-container svg, .visual-container img {
            width: 100%;
            height: auto;
        }

        /* About Section Styles */
        .about-grid {
            display: grid;
            grid-template-columns: 1.1fr 0.9fr;
            gap: 3.5rem;
            align-items: center;
        }

        .skills-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 0.5rem;
            margin-top: 1.25rem;
        }

        .skill-badge {
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            color: var(--text-body);
            padding: 0.35rem 0.75rem;
            border-radius: 4px;
            font-size: 0.8rem;
            font-weight: 600;
            transition: background var(--transition-speed), border-color var(--transition-speed), color var(--transition-speed);
        }

        .skill-badge:hover {
            background-color: var(--primary);
            border-color: var(--primary);
            color: #ffffff;
        }

        .about-visual {
            display: flex;
            justify-content: center;
            width: 100%;
        }

        .about-img {
            width: 100%;
            height: auto;
            border-radius: 8px;
            border: 1px solid var(--border-color);
            box-shadow: 0 4px 12px rgba(0,0,0,0.02);
            background-color: var(--bg-section);
            display: block;
        }

        /* Section structure */
        section {
            padding: 85px 0;
            border-bottom: 1px solid var(--border-color);
            position: relative;
        }

        section:nth-child(even) {
            background-color: var(--bg-section);
        }

        .section-header {
            text-align: center;
            max-width: 580px;
            margin: 0 auto 3.5rem auto;
        }

        .section-header p {
            margin-top: 0.75rem;
            color: var(--text-muted);
        }

        /* Grid layout utilities */
        .grid-cards {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 1.5rem;
        }

        /* Stylized Minimalist Cards */
        .card {
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            padding: 2rem;
            transition: background-color var(--transition-speed), border-color var(--transition-speed), box-shadow var(--transition-speed);
            display: flex;
            flex-direction: column;
            height: 100%;
        }

        .card:hover {
            background-color: var(--bg-card-hover);
            border-color: #cbd5e1;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
        }

        .card-icon {
            width: 48px;
            height: 48px;
            background-color: var(--bg-section);
            border: 1px solid var(--border-color);
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--primary);
            margin-bottom: 1.25rem;
            transition: background-color var(--transition-speed), color var(--transition-speed);
        }

        .card:hover .card-icon {
            color: #ffffff;
            background-color: var(--primary);
            border-color: var(--primary);
        }

        .card-icon svg {
            width: 24px;
            height: 24px;
            fill: none;
            stroke: currentColor;
            stroke-width: 2;
            stroke-linecap: round;
            stroke-linejoin: round;
        }

        .card-title {
            margin-bottom: 0.5rem;
        }

        .card-desc {
            font-size: 0.95rem;
            color: var(--text-body);
            line-height: 1.5;
        }

        /* References / Portfolio Section */
        .references-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
            gap: 1.5rem;
        }

        .ref-card {
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 8px;
            overflow: hidden;
            transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
            display: flex;
            flex-direction: column;
        }

        .ref-card:hover {
            border-color: #cbd5e1;
            box-shadow: 0 4px 16px rgba(0, 0, 0, 0.04);
        }

        .ref-mockup {
            width: 100%;
            background-color: var(--bg-section);
            overflow: hidden;
            display: flex;
            align-items: center;
            justify-content: center;
            border-bottom: 1px solid var(--border-color);
        }

        .ref-img {
            width: 100%;
            height: 100%;
            object-fit: cover;
            display: block;
            background-color: var(--bg-section);
        }

        .ref-info {
            padding: 1.25rem;
            display: flex;
            flex-direction: column;
            flex-grow: 1;
        }

        .ref-tag {
            font-size: 0.65rem;
            text-transform: uppercase;
            font-weight: 700;
            color: var(--primary);
            letter-spacing: 0.5px;
            margin-bottom: 0.4rem;
            display: inline-block;
        }

        .ref-title {
            font-size: 1.05rem;
            margin-bottom: 0.4rem;
            color: var(--text-heading);
            word-break: break-all;
        }

        .ref-desc {
            font-size: 0.85rem;
            line-height: 1.45;
            color: var(--text-muted);
            margin-bottom: 1rem;
            flex-grow: 1;
        }

        .ref-link {
            font-size: 0.8rem;
            font-weight: 600;
            color: var(--primary);
            display: inline-flex;
            align-items: center;
            gap: 0.2rem;
            margin-top: auto;
        }

        .ref-link svg {
            width: 12px;
            height: 12px;
            transition: transform 0.2s;
            stroke-width: 2.5;
        }

        .ref-card:hover .ref-link svg {
            transform: translateX(3px);
        }

        /* Why Us Section */
        .why-us-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 3.5rem;
            align-items: center;
        }

        .why-us-stats {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1.5rem;
        }

        .stat-box {
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            padding: 1.75rem 1.25rem;
            border-radius: 8px;
            text-align: center;
        }

        .stat-num {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--primary);
            line-height: 1.1;
            margin-bottom: 0.4rem;
            letter-spacing: -0.03em;
        }

        .stat-label {
            font-size: 0.95rem;
            color: var(--text-heading);
            font-weight: 600;
            margin-bottom: 0.2rem;
        }

        .stat-sub {
            font-size: 0.8rem;
            color: var(--text-muted);
        }

        .why-us-list {
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 1.25rem;
        }

        .why-us-item {
            display: flex;
            gap: 1rem;
            align-items: flex-start;
        }

        .why-us-check {
            width: 24px;
            height: 24px;
            background-color: #eff6ff;
            color: var(--primary);
            border-radius: 4px;
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            margin-top: 0.15rem;
        }

        .why-us-check svg {
            width: 14px;
            height: 14px;
            stroke-width: 3;
        }

        .why-us-item h3 {
            margin-bottom: 0.15rem;
        }

        .why-us-item p {
            font-size: 0.95rem;
            color: var(--text-body);
        }

        /* Contact Section styling */
        .contact-grid {
            display: grid;
            grid-template-columns: 0.9fr 1.1fr;
            gap: 3.5rem;
            align-items: start;
        }

        .contact-info {
            display: flex;
            flex-direction: column;
            gap: 1.75rem;
        }

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

        .contact-icon {
            width: 44px;
            height: 44px;
            background-color: var(--bg-section);
            border: 1px solid var(--border-color);
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-heading);
            flex-shrink: 0;
        }

        .contact-icon svg {
            width: 20px;
            height: 20px;
            fill: none;
            stroke: currentColor;
            stroke-width: 2;
        }

        .contact-item h3 {
            font-size: 1rem;
            margin-bottom: 0.15rem;
        }

        .contact-item a:hover {
            color: var(--primary);
        }

        .social-links {
            display: flex;
            gap: 0.75rem;
            margin-top: 0.75rem;
        }

        .social-btn {
            width: 38px;
            height: 38px;
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 6px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--text-muted);
            transition: color var(--transition-speed), background var(--transition-speed), border-color var(--transition-speed);
        }

        .social-btn:hover {
            color: #ffffff;
            background-color: var(--primary);
            border-color: var(--primary);
        }

        .social-btn svg {
            width: 16px;
            height: 16px;
            fill: currentColor;
        }

        /* Form styling */
        .contact-form {
            background-color: var(--bg-card);
            border: 1px solid var(--border-color);
            padding: 2rem;
            border-radius: 8px;
            position: relative;
        }

        .form-group {
            margin-bottom: 1.25rem;
            display: flex;
            flex-direction: column;
            gap: 0.4rem;
        }

        .form-label {
            font-size: 0.85rem;
            font-weight: 600;
            color: var(--text-heading);
        }

        .form-control {
            width: 100%;
            background-color: #ffffff;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            padding: 0.75rem 0.9rem;
            color: var(--text-heading);
            transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
        }

        .form-control:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
        }

        textarea.form-control {
            resize: vertical;
            min-height: 110px;
        }

        /* Form Feedback Alert */
        .form-alert {
            padding: 0.75rem 1rem;
            border-radius: 4px;
            margin-bottom: 1.25rem;
            font-weight: 500;
            font-size: 0.9rem;
            display: none;
        }

        .form-alert-success {
            background-color: #ecfdf5;
            border: 1px solid #a7f3d0;
            color: #065f46;
        }

        .form-alert-error {
            background-color: #fef2f2;
            border: 1px solid #fca5a5;
            color: #991b1b;
        }

        /* Footer Section */
        footer {
            background-color: var(--bg-section);
            padding: 40px 0;
            border-top: 1px solid var(--border-color);
            text-align: center;
        }

        .footer-wrap {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 1.25rem;
        }

        .footer-links {
            display: flex;
            gap: 1.5rem;
            list-style: none;
            font-size: 0.85rem;
            color: var(--text-muted);
        }

        .footer-links a:hover {
            color: var(--text-heading);
        }

        /* Back to top button */
        .back-to-top {
            position: fixed;
            bottom: 2rem;
            right: 2rem;
            background-color: var(--secondary);
            color: #ffffff;
            width: 40px;
            height: 40px;
            border-radius: 4px;
            border: none;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.25s, visibility 0.25s, background-color 0.2s, transform 0.2s;
            z-index: 800;
        }

        .back-to-top.show {
            opacity: 1;
            visibility: visible;
        }

        .back-to-top:hover {
            background-color: var(--primary);
            transform: translateY(-2px);
        }

        .back-to-top svg {
            width: 16px;
            height: 16px;
            fill: none;
            stroke: currentColor;
            stroke-width: 2.5;
        }

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

        .mt-4 {
            margin-top: 1.5rem;
        }

        /* Media Queries (Mobile Responsive Structure) */
        @media (max-width: 992px) {
            .hero-grid {
                grid-template-columns: 1fr;
                gap: 2.5rem;
                text-align: center;
            }

            .hero-content {
                max-width: 100%;
                display: flex;
                flex-direction: column;
                align-items: center;
            }

            .hero-badge {
                align-self: center;
            }

            .hero-ctas {
                justify-content: center;
            }

            .about-grid {
                grid-template-columns: 1fr;
                gap: 2.5rem;
                text-align: center;
            }

            .skills-grid {
                justify-content: center;
            }

            .why-us-grid {
                grid-template-columns: 1fr;
                gap: 2.5rem;
            }

            .contact-grid {
                grid-template-columns: 1fr;
                gap: 2.5rem;
            }
        }

        @media (max-width: 768px) {
            .header-wrap {
                height: 65px;
            }

            .menu-toggle {
                display: block;
            }

            .footer-links {
                flex-direction: column;
                gap: 0.75rem;
            }

            /* Nav transitions on mobile */
            nav {
                position: fixed;
                top: 65px;
                left: 0;
                width: 100%;
                height: calc(100vh - 65px);
                background-color: #ffffff;
                flex-direction: column;
                justify-content: center;
                gap: 2.5rem;
                transform: translateX(100%);
                transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
                border-top: 1px solid var(--border-color);
                z-index: 999;
            }

            nav.open {
                transform: translateX(0);
            }

            .nav-links {
                flex-direction: column;
                align-items: center;
                gap: 1.5rem;
            }

            .nav-links a {
                font-size: 1.15rem;
            }

            .hero {
                padding: 110px 0 50px 0;
            }

            .btn {
                width: 100%;
            }

            .stat-box {
                padding: 1.5rem 1rem;
            }
        }

        /* Sticky Floating Contact Buttons (Bottom Left) */
        .floating-contact {
            position: fixed;
            bottom: 2rem;
            left: 2rem;
            display: flex;
            flex-direction: column;
            gap: 0.75rem;
            z-index: 999;
        }

        .floating-btn {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #ffffff;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            transition: transform 0.3s, box-shadow 0.3s;
            cursor: pointer;
            text-decoration: none;
            position: relative;
        }

        .floating-btn:hover {
            transform: scale(1.1);
            box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
        }

        .floating-btn-wp {
            background-color: #25d366; /* WhatsApp Green */
        }

        .floating-btn-call {
            background-color: #2563eb; /* Phone Blue */
        }

        .floating-btn svg {
            width: 24px;
            height: 24px;
            fill: currentColor;
        }

        /* Tooltip style */
        .floating-btn::after {
            content: attr(data-tooltip);
            position: absolute;
            left: 60px;
            background-color: #0f172a;
            color: #ffffff;
            padding: 0.4rem 0.75rem;
            border-radius: 4px;
            font-size: 0.8rem;
            font-weight: 500;
            white-space: nowrap;
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.3s, visibility 0.3s;
            box-shadow: 0 2px 8px rgba(0,0,0,0.15);
        }

        .floating-btn:hover::after {
            opacity: 1;
            visibility: visible;
        }

        @media (max-width: 768px) {
            .floating-contact {
                bottom: 1.5rem;
                left: 1.5rem;
            }
            .floating-btn {
                width: 46px;
                height: 46px;
            }
            .floating-btn svg, .floating-btn i {
                width: 22px;
                height: 22px;
                font-size: 20px;
                line-height: 22px;
            }
        }

        /* Font Awesome icon resizing */
        .card-icon i {
            font-size: 20px;
        }
        .contact-icon i {
            font-size: 18px;
        }
        .floating-btn i {
            font-size: 22px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .social-btn i {
            font-size: 18px;
            display: flex;
            align-items: center;
            justify-content: center;
            height: 100%;
        }