:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-card: #ffffff;
    --text-primary: #1f2328;
    --text-secondary: #57606a;
    --text-muted: #8b949e;
    --accent-teal: #1b6f82;
    --accent-teal-rgb: 27, 111, 130;
    --accent-teal-dark: #12505e;
    --accent-teal-light: #e6f2f4;
    --accent-green: #1a7f37;
    --accent-red: #cf222e;
    --border-color: #e2e6ea;
    --input-bg: #ffffff;
    --shadow: 0 8px 24px rgba(140, 149, 159, 0.15);
    --shadow-sm: 0 1px 3px rgba(140, 149, 159, 0.2);
    --nav-scrolled-bg: rgba(255, 255, 255, 0.9);
    --nav-outline-bg: rgba(255, 255, 255, 0.7);
    --font-main: 'Inter', sans-serif;
    --nav-h: 76px;
    --radius: 18px;
}

:root[data-theme="dark"] {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-card: #1c2128;
    --text-primary: #e6edf3;
    --text-secondary: #9198a1;
    --text-muted: #6e7681;
    --accent-teal: #3fb1c9;
    --accent-teal-rgb: 63, 177, 201;
    --accent-teal-dark: #6ec6da;
    --accent-teal-light: rgba(63, 177, 201, 0.15);
    --accent-green: #3fb950;
    --accent-red: #ff7b72;
    --border-color: #30363d;
    --input-bg: #0d1117;
    --shadow: 0 8px 24px rgba(0, 0, 0, 0.45);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.35);
    --nav-scrolled-bg: rgba(13, 17, 23, 0.85);
    --nav-outline-bg: rgba(28, 33, 40, 0.6);
}

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

body {
    font-family: var(--font-main);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.top-nav {
    position: fixed; top: 0; left: 0; width: 100%; height: var(--nav-h);
    padding: 0 2rem;
    display: flex; align-items: center; justify-content: space-between; gap: 1rem;
    z-index: 1000; transition: background 0.3s, border-color 0.3s;
    border-bottom: 1px solid transparent;
}
.top-nav.scrolled { background: var(--nav-scrolled-bg); backdrop-filter: blur(12px); border-bottom-color: var(--border-color); }
.nav-logo { display: inline-flex; }
.nav-logo img { height: 40px; width: auto; display: block; }
.logo-koyu { display: none !important; }
:root[data-theme="dark"] .logo-acik { display: none !important; }
:root[data-theme="dark"] .logo-koyu { display: block !important; }
.nav-links { display: flex; gap: 0.75rem; align-items: center; }
.nav-btn {
    padding: 0.6rem 1.2rem; border-radius: 8px; font-size: 0.9rem; font-weight: 500;
    text-decoration: none; transition: all 0.2s; display: inline-flex; align-items: center; gap: 0.5rem;
}
.nav-btn-outline { border: 1px solid var(--border-color); color: var(--text-primary); background: var(--nav-outline-bg); }
.nav-btn-outline:hover { border-color: var(--accent-teal); color: var(--accent-teal); }
.nav-btn-primary { background: var(--accent-teal); color: #ffffff; border: 1px solid var(--accent-teal); }
.nav-btn-primary:hover { background: var(--accent-teal-dark); border-color: var(--accent-teal-dark); }
.theme-toggle-btn {
    width: 40px; height: 40px; border-radius: 50%; border: 1px solid var(--border-color);
    background: var(--nav-outline-bg); color: var(--text-primary); font-size: 1.05rem;
    display: inline-flex; align-items: center; justify-content: center; cursor: pointer; transition: all 0.2s;
    text-decoration: none;
}
.theme-toggle-btn:hover { border-color: var(--accent-teal); color: var(--accent-teal); }

.eyebrow { font-size: 0.8rem; font-weight: 700; letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent-teal); }

.btn {
    padding: 0.9rem 1.8rem; border-radius: 10px; font-weight: 600; font-size: 1rem; text-decoration: none; cursor: pointer;
    display: inline-flex; align-items: center; gap: 0.55rem; transition: background 0.2s, border-color 0.2s, color 0.2s; border: 1px solid transparent;
}
.btn-primary { background: var(--accent-teal); color: #fff; box-shadow: 0 10px 24px rgba(var(--accent-teal-rgb), 0.28); }
.btn-primary:hover { background: var(--accent-teal-dark); }
.btn-outline { border-color: var(--border-color); color: var(--text-primary); background: var(--bg-card); }
.btn-outline:hover { border-color: var(--accent-teal); color: var(--accent-teal); }

.kart-kutu {
    background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); box-shadow: var(--shadow);
}
.ikon-rozet {
    width: 46px; height: 46px; flex-shrink: 0; border-radius: 13px; display: inline-flex; align-items: center; justify-content: center;
    background: var(--accent-teal-light); color: var(--accent-teal); font-size: 1.3rem;
}

@media (max-width: 768px) {
    .top-nav { padding: 0 1.25rem; }
    .nav-btn span { display: none; }
    .nav-btn { padding: 0.55rem 0.7rem; }
}