/* --- Variables (can be shared with home.css or defined separately) --- */
:root {
    --primary-color: #164b92;
    --secondary-color: #0f3a75;
    --text-color-light: #333333;
    --text-color-dark: #e0e0e0;
    --bg-light: #ffffff;
    --bg-dark: #121f3a; /* Dark Desaturated Blue */
    --header-height: 70px;
    --header-height-scrolled: 60px;
    --border-radius: 8px;
    --transition-speed: 0.3s;
    --font-primary: 'Poppins', sans-serif;
}

html[data-theme="dark"] {
    --primary-color-dark-accent: #4a90e2; /* Brighter blue for dark mode */
    --secondary-color-dark: #2a4a87;
}

/* --- Base Header Styles --- */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    height: var(--header-height);
    background-color: transparent; /* Start transparent */
    box-shadow: none;
    transition: background-color var(--transition-speed) ease,
                height var(--transition-speed) ease,
                box-shadow var(--transition-speed) ease,
                transform var(--transition-speed) ease; /* Added transform transition */
    transform: translateY(0); /* Default state */
    opacity: 0; /* Start hidden */
    visibility: hidden; /* Start hidden */
}

/* --- Header Appearance Logic (Controlled by JS) --- */
.site-header.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
    transition: opacity 0.5s ease, visibility 0s linear 0s, transform 0.5s ease;
}

/* --- Scrolled State --- */
.site-header.scrolled {
    height: var(--header-height-scrolled);
    background-color: var(--bg-light);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

html[data-theme="dark"] .site-header.scrolled {
    background-color: var(--bg-dark);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

/* --- Header Container --- */
.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 15px;
    max-width: 1200px; /* Consistent with main container */
    margin: 0 auto;
}

@media (min-width: 768px) {
    .header-container {
        padding: 0 20px;
    }
}

/* --- Logo --- */
.header-logo-link {
    display: inline-block;
    height: 70%; /* Adjust percentage as needed */
    transition: height var(--transition-speed) ease;
}

.site-header.scrolled .header-logo-link {
    height: 65%; /* Slightly smaller logo when scrolled */
}

.header-logo {
    height: 100%;
    width: auto;
    object-fit: contain;
    display: block;
}

/* Logo Dark/Light Mode Handling */
.logo-dark { display: none; } /* Hide dark logo by default */
html[data-theme="dark"] .logo-light { display: none; } /* Hide light logo in dark mode */
html[data-theme="dark"] .logo-dark { display: block; } /* Show dark logo in dark mode */

/* --- Navigation --- */
.header-nav {
    display: none; /* Hidden on mobile by default */
}

@media (min-width: 992px) { /* Show on larger screens */
    .header-nav {
        display: block;
    }
}

.nav-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 5px; /* Spacing between links */
}

.nav-link {
    display: inline-block;
    padding: 10px 15px; /* Adjust padding */
    font-family: var(--font-primary);
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--text-color-light); /* Default text color (for scrolled light mode) */
    text-decoration: none;
    border-radius: 5px;
    position: relative;
    overflow: hidden; /* For hover effect */
    transition: color var(--transition-speed) ease, background-color var(--transition-speed) ease;
}

.nav-link span {
    position: relative; /* For pseudo-element positioning */
    z-index: 1;
}

/* Initial state color (when header is transparent) */
.site-header:not(.scrolled) .nav-link {
    color: #ffffff; /* White text on video */
    text-shadow: 0 1px 2px rgba(0,0,0,0.4);
}

/* Override for non-home pages - make nav text completely invisible when not scrolled */
body:not(.home-page) .site-header:not(.scrolled) .nav-link {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity var(--transition-speed) ease, visibility var(--transition-speed) ease;
}

/* Scrolled light mode color */
.site-header.scrolled .nav-link {
    color: var(--text-color-light) !important; /* Dark text on light background */
}

/* Scrolled dark mode color */
html[data-theme="dark"] .site-header.scrolled .nav-link {
    color: var(--text-color-dark) !important;
}

/* Underline Hover/Active Effect */
.nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-speed) ease;
}

.site-header:not(.scrolled) .nav-link::before {
    background-color: #ffffff; /* White underline on video */
}

html[data-theme="dark"] .site-header.scrolled .nav-link::before {
    background-color: var(--primary-color-dark-accent);
}

.nav-link:hover::before,
.nav-link.active::before {
    transform: scaleX(1);
}

/* Active link style adjustment */
.nav-link.active {
    font-weight: 600; /* Slightly bolder */
}

.site-header:not(.scrolled) .nav-link:hover,
.site-header:not(.scrolled) .nav-link.active {
    color: #ffffff; /* Ensure white text on hover/active on video */
}

.site-header.scrolled .nav-link:hover,
.site-header.scrolled .nav-link.active {
     color: var(--primary-color); /* Primary color on hover/active (light mode) */
}

html[data-theme="dark"] .site-header.scrolled .nav-link:hover,
html[data-theme="dark"] .site-header.scrolled .nav-link.active {
    color: var(--primary-color-dark-accent); /* Accent color on hover/active (dark mode) */
}


/* --- Hamburger Button --- */
.hamburger-btn {
    display: flex; /* Show by default, hide nav instead */
    flex-direction: column;
    justify-content: space-around;
    width: 28px;
    height: 22px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: 1010;
    margin-left: 15px; /* Space from edge */
}

.hamburger-btn span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--text-color-light); /* Default color */
    border-radius: 2px;
    transition: all var(--transition-speed) ease-in-out;
}

/* Hamburger color when header is transparent */
.site-header:not(.scrolled) .hamburger-btn span {
     background-color: #ffffff;
}
/* Hamburger color in scrolled dark mode */
html[data-theme="dark"] .site-header.scrolled .hamburger-btn span {
     background-color: var(--text-color-dark);
}

/* Hamburger Animation (Active State) */
.hamburger-btn.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.hamburger-btn.active span:nth-child(2) {
    opacity: 0;
    transform: translateX(-10px);
}

.hamburger-btn.active span:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

@media (min-width: 992px) { /* Hide hamburger on larger screens */
    .hamburger-btn {
        display: none;
    }
}

/* --- Mobile Navigation Menu (Off-Canvas or Dropdown) --- */
@media (max-width: 991.98px) {
    .header-nav {
        display: block; /* Make it available */
        position: fixed;
        top: 0; /* Position relative to viewport */
        left: 0;
        width: 100%;
        height: 100vh; /* Full height */
        background-color: var(--bg-light);
        padding-top: calc(var(--header-height) + 20px); /* Space below header */
        transform: translateX(-100%); /* Start off-screen */
        transition: transform 0.4s cubic-bezier(0.23, 1, 0.32, 1); /* Smooth transition */
        overflow-y: auto; /* Allow scrolling if needed */
        z-index: 999; /* Below header but above content */
    }

    html[data-theme="dark"] .header-nav {
        background-color: var(--bg-dark);
    }

    .header-nav.active {
        transform: translateX(0); /* Slide in */
    }

    .nav-list {
        flex-direction: column;
        align-items: center;
        padding: 20px 0;
        gap: 0; /* Reset gap */
    }

    .nav-list li {
       width: 100%;
       text-align: center;
       opacity: 0; /* For staggered animation */
       transform: translateY(20px); /* For staggered animation */
       transition: opacity 0.3s ease, transform 0.3s ease;
    }

    /* Staggered animation for list items */
    .header-nav.active .nav-list li {
        opacity: 1;
        transform: translateY(0);
    }
    .header-nav.active .nav-list li:nth-child(1) { transition-delay: 0.1s; }
    .header-nav.active .nav-list li:nth-child(2) { transition-delay: 0.15s; }
    .header-nav.active .nav-list li:nth-child(3) { transition-delay: 0.2s; }
    .header-nav.active .nav-list li:nth-child(4) { transition-delay: 0.25s; }
    .header-nav.active .nav-list li:nth-child(5) { transition-delay: 0.3s; }
    /* Add more delays if needed */


    .nav-link {
        padding: 15px 20px;
        font-size: 1.1rem; /* Larger font for mobile menu */
        width: 100%;
        /* Don't override color here - let the main styles handle it */
    }

     html[data-theme="dark"] .nav-link {
        color: var(--text-color-dark);
    }

    .nav-link:hover,
    .nav-link.active {
        background-color: rgba(0, 0, 0, 0.05); /* Subtle background */
    }

    html[data-theme="dark"] .nav-link:hover,
    html[data-theme="dark"] .nav-link.active {
        background-color: rgba(255, 255, 255, 0.05);
    }

    /* Remove underline effect on mobile */
    .nav-link::before {
        display: none;
    }
}