/* ========================================
   BBN GRUP BİLİŞİM TEKNOLOJİ - Ana Stil
   Tema: Premium Kurumsal
   Teknoloji: CSS3, Glassmorphism, Dark/Light
   ======================================== */

/* ---------- CSS Değişkenleri ---------- */
:root {
    /* Renkler */
    --primary: #0057B8;
    --secondary: #0B1F3A;
    --accent: #00C2FF;
    --success: #16C784;
    --bg-light: #F8FAFC;
    --bg-dark: #0A0E1A;
    --text-light: #1E293B;
    --text-dark: #E2E8F0;
    --glass-bg: rgba(255, 255, 255, 0.12);
    --glass-border: rgba(255, 255, 255, 0.18);
    --shadow-soft: 0 10px 40px rgba(0, 0, 0, 0.08);
    --shadow-glass: 0 8px 32px rgba(0, 87, 184, 0.15);
    --radius: 16px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

/* Dark Mode Değişkenleri */
[data-theme="dark"] {
    --bg-light: #0A0E1A;
    --text-light: #E2E8F0;
    --glass-bg: rgba(255, 255, 255, 0.06);
    --glass-border: rgba(255, 255, 255, 0.12);
    --shadow-soft: 0 10px 40px rgba(0, 0, 0, 0.4);
    --shadow-glass: 0 8px 32px rgba(0, 87, 184, 0.25);
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-light);
    color: var(--text-light);
    line-height: 1.6;
    transition: background-color 0.4s, color 0.4s;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
}

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

ul {
    list-style: none;
}

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ---------- Tipografi ---------- */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.4rem, 6vw, 4.2rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.4rem, 2.5vw, 1.8rem); }

.section-title {
    position: relative;
    margin-bottom: 1.5rem;
}
.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    border-radius: 4px;
    margin-top: 12px;
}
.text-center .section-title::after {
    margin-left: auto;
    margin-right: auto;
}

/* ---------- Butonlar ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 32px;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    background: transparent;
    color: var(--text-light);
    box-shadow: var(--shadow-soft);
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover {
    background: #004099;
    transform: translateY(-3px);
    box-shadow: 0 12px 30px rgba(0, 87, 184, 0.35);
}

.btn-outline {
    border: 2px solid var(--primary);
    color: var(--primary);
    background: transparent;
}
.btn-outline:hover {
    background: var(--primary);
    color: #fff;
    transform: translateY(-3px);
}

.btn-accent {
    background: var(--accent);
    color: #fff;
}
.btn-accent:hover {
    background: #00a3d6;
    transform: translateY(-3px);
}

/* ---------- Glassmorphism Kart ---------- */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-glass);
    transition: var(--transition);
    padding: 2rem;
}
.glass-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 16px 48px rgba(0, 87, 184, 0.2);
}

/* ---------- Header / Navbar ---------- */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 12px 0;
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: var(--transition);
}
[data-theme="dark"] .header {
    background: rgba(10, 14, 26, 0.8);
}
.header.scrolled {
    box-shadow: 0 4px 30px rgba(0,0,0,0.08);
}

.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
}
.logo img {
    height: 44px;
    width: auto;
}

.nav-menu {
    display: flex;
    gap: 8px;
    align-items: center;
}
.nav-menu a {
    padding: 8px 16px;
    border-radius: 30px;
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition);
    position: relative;
}
.nav-menu a:hover,
.nav-menu a.active {
    background: var(--primary);
    color: #fff;
}

/* Mobile Menu */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
}
.hamburger span {
    width: 28px;
    height: 3px;
    background: var(--text-light);
    border-radius: 4px;
    transition: var(--transition);
}

@media (max-width: 992px) {
    .hamburger { display: flex; }
    .nav-menu {
        display: none;
        flex-direction: column;
        width: 100%;
        padding: 20px 0;
        background: var(--bg-light);
        border-radius: var(--radius);
        margin-top: 16px;
        box-shadow: var(--shadow-soft);
    }
    .nav-menu.open {
        display: flex;
    }
    .nav-menu a {
        width: 100%;
        text-align: center;
        padding: 12px;
    }
}

/* ---------- Mega Menü (örnek) ---------- */
.mega-menu {
    position: relative;
}
.mega-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    width: 700px;
    background: var(--bg-light);
    backdrop-filter: blur(20px);
    border-radius: var(--radius);
    box-shadow: var(--shadow-soft);
    padding: 24px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: var(--transition);
}
.mega-menu:hover .mega-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* ---------- Hero ---------- */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: 120px 0 80px;
    background: linear-gradient(135deg, var(--secondary), #0a1a2f);
    color: #fff;
    overflow: hidden;
}
.hero-bg-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.25;
    z-index: 0;
}
.hero-content {
    position: relative;
    z-index: 2;
    max-width: 720px;
}
.hero h1 {
    margin-bottom: 1.5rem;
}
.hero p {
    font-size: 1.2rem;
    opacity: 0.85;
    margin-bottom: 2rem;
    max-width: 580px;
}
.hero .btn-group {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
}

/* Hero istatistikleri */
.hero-stats {
    display: flex;
    flex-wrap: wrap;
    gap: 32px;
    margin-top: 48px;
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 40px;
}
.stat-item {
    text-align: center;
}
.stat-number {
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--accent);
}
.stat-label {
    font-size: 0.9rem;
    opacity: 0.7;
}

/* ---------- Hizmetler Kartları ---------- */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}
.service-card {
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    border-radius: var(--radius);
    padding: 2rem;
    border: 1px solid var(--glass-border);
    transition: var(--transition);
    text-align: center;
}
.service-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-glass);
}
.service-card .icon {
    font-size: 3rem;
    color: var(--primary);
    margin-bottom: 1rem;
}
.service-card h3 {
    margin-bottom: 0.75rem;
}
.service-card p {
    opacity: 0.8;
    font-size: 0.95rem;
}

/* ---------- Footer ---------- */
.footer {
    background: var(--secondary);
    color: rgba(255,255,255,0.8);
    padding: 60px 0 30px;
}
.footer a {
    color: rgba(255,255,255,0.6);
    transition: var(--transition);
}
.footer a:hover {
    color: #fff;
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}
.footer h4 {
    color: #fff;
    margin-bottom: 1rem;
}
.footer ul li {
    margin-bottom: 8px;
}
.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.08);
    padding-top: 24px;
    text-align: center;
    font-size: 0.9rem;
}

/* ---------- Dark/Light Toggle ---------- */
.theme-toggle {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 50px;
    padding: 8px 16px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition);
}
.theme-toggle:hover {
    background: var(--primary);
    color: #fff;
}

/* ---------- Scroll Progress Bar ---------- */
.scroll-progress {
    position: fixed;
    top: 0;
    left: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary), var(--accent));
    z-index: 9999;
    width: 0%;
    transition: width 0.1s;
}

/* ---------- Back to Top ---------- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--primary);
    color: #fff;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    box-shadow: var(--shadow-soft);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
    cursor: pointer;
}
.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}
.back-to-top:hover {
    transform: translateY(-5px);
    background: var(--accent);
}

/* ---------- Responsive Fine-Tuning ---------- */
@media (max-width: 768px) {
    .hero {
        padding: 100px 0 60px;
        text-align: center;
    }
    .hero p {
        margin-left: auto;
        margin-right: auto;
    }
    .hero .btn-group {
        justify-content: center;
    }
    .hero-stats {
        justify-content: center;
    }
    .section-title::after {
        margin-left: auto;
        margin-right: auto;
    }
}