/* ============================================= */
/* === Header & Navigation                   === */
/* ============================================= */
.site-header {
    background-color: rgba(20, 20, 20, 0.8); /* Semi-transparent dark background */
    padding: 15px 0;                      /* Vertical padding */
    position: fixed;                      /* Fixed position at the top */
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;                        /* Ensures header stays above other content */
    /* box-shadow: 0 2px 5px rgba(0,0,0,0.1); Optional subtle shadow */
}

.nav-container { /* Flex container for logo, nav links, and login button */
    display: flex;
    justify-content: space-between; /* Pushes logo/button to ends, nav to center */
    align-items: center;            /* Vertically aligns items */
}

.logo-image { /* Styling for the logo in the header */
    height: 40px;
    width: auto;  /* Maintain aspect ratio */
}

.main-nav ul { /* Flex container for navigation links */
    display: flex;
}

.main-nav ul li { /* Each navigation list item */
    margin-left: 25px; /* Spacing between nav links */
}

.main-nav ul li a { /* Individual navigation links */
    color: #fff;          /* White text color */
    padding-bottom: 5px; /* Space for the active link border */
    font-weight: 500;
    transition: color 0.3s ease; /* Smooth color transition on hover */
    position: relative;          /* For pseudo-element underline on hover (optional) */
}

/* Active and hover states for navigation links */
.main-nav ul li a.active,
.main-nav ul li a:hover {
    color: #4CAF50; /* Green accent color */
}

/* Underline for the active navigation link */
.main-nav ul li a.active {
    border-bottom: 2px solid #4CAF50;
}

.btn-login { /* Login button style in the navigation */
    color: #fff;
    border: 1px solid #4CAF50;
    padding: 8px 18px;
    border-radius: 5px;
    font-weight: 500;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.btn-login:hover {
    background-color: #4CAF50;
    color: #fff;
}

/* --- Header & Navigation (Mobile: max-width: 768px) --- */
@media (max-width: 768px) {
    .site-header {
        position: relative; /* Changed from fixed for simpler mobile nav */
        padding-bottom: 15px;
    }
    .nav-container {
        flex-direction: column;
    }
    .logo-link { /* Assuming .logo-image is inside .logo-link */
        margin-bottom: 15px;
    }
    .main-nav ul {
        flex-direction: column;
        align-items: center;
        width: 100%;
    }
    .main-nav ul li {
        margin: 10px 0;
    }
    .btn-login {
        margin-top: 15px;
        display: inline-block;
    }
}