/* ==========================================================================
   Header Section (from original CSS)
   ========================================================================== */
   header {
    height: 60px;
    background-color: rgba(255, 255, 255, 0.85);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(15px);
    border-bottom: 1px solid rgba(114, 137, 157, 0.1);
}

header .container {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    /* Inherits container padding from main.css */
    /* max-width is defined in main.css :root and applied via .container */
}

.logo-link {
    display: block;
    text-decoration: none;
    transition: transform 0.3s ease;
}
.logo-link:hover {
    transform: scale(1.05);
}
.logo {
    width: 120px;
    height: auto;
    display: block;
}

/* Main Navigation */
.main-nav {
    margin-left: auto;
}
.main-nav > ul { /* Direct child ul only */
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 32px;
}
.main-nav > ul > li {
    position: relative; /* For dropdown positioning */
}
.main-nav > ul > li > a { /* Top-level links only */
    color: var(--text-color); /* Needs --text-color from main.css */
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    padding: 8px 0;
    position: relative;
    transition: color 0.3s ease;
}
.main-nav > ul > li > a::after { /* Underline animation for top-level links */
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background-color: var(--primary-color); /* Needs --primary-color from main.css */
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.3s ease;
}
.main-nav > ul > li > a:hover,
.main-nav > ul > li > a.active {
    color: var(--primary-color); /* Needs --primary-color from main.css */
}
.main-nav > ul > li > a:hover::after,
.main-nav > ul > li > a.active::after {
    transform: scaleX(1);
    transform-origin: left;
}
.main-nav > ul > li > a.active {
    font-weight: 700;
}

/* Dropdown Menu */
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(-10px); /* Adjusted initial position slightly */
    background-color: white;
    min-width: 200px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
    border-radius: 4px;
    padding: 8px 0;
    z-index: 1000;
    opacity: 0;
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s;
    pointer-events: none;
    visibility: hidden;
}
.has-dropdown:hover .dropdown-menu {
    visibility: visible;
    opacity: 1;
    transform: translateX(-50%) translateY(8px); /* Final position with gap */
    pointer-events: auto;
}
/* Triangle decoration */
.dropdown-menu::before {
    content: '';
    position: absolute;
    top: -4px; /* Position above the menu */
    left: 50%;
    transform: translateX(-50%) rotate(45deg);
    width: 8px;
    height: 8px;
    background: white;
    box-shadow: -1px -1px 1px rgba(0,0,0,0.05); /* Subtle shadow */
    z-index: -1; /* Behind the menu content */
}
.dropdown-menu a {
    display: block;
    padding: 10px 16px;
    color: var(--text-color); /* Needs --text-color from main.css */
    text-decoration: none;
    transition: background-color 0.2s ease, color 0.2s ease;
    font-size: 14px;
    position: relative;
}
/* Remove underlines from dropdown links */
.dropdown-menu a::after {
    display: none !important;
}
.dropdown-menu a:hover {
    background-color: var(--bg-color); /* Needs --bg-color from main.css */
    color: var(--primary-color); /* Needs --primary-color from main.css */
}

/* ==========================================================================
   Responsive Header Styles (from original CSS)
   ========================================================================== */

/* Tablets */
@media (max-width: 768px) {
    header { height: 60px; }
    .logo { width: 120px; }
    .main-nav > ul { gap: 24px; }
    .main-nav > ul > li > a { font-size: 14px; }
    .dropdown-menu { min-width: 180px; }
    .dropdown-menu a { padding: 8px 14px; font-size: 13px; }
}

/* Smaller Mobiles */
@media (max-width: 576px) {
    header { height: 60px; }
    .logo { width: 110px; }
    .main-nav { /* Consider a hamburger menu here */
        display: none; /* Example: Hide nav, replace with hamburger */
    }
    /* Add styles for hamburger menu if implemented */
}

/* ハンバーガーメニューのスタイル */
.hamburger {
    display: none;
    background: none;
    border: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    cursor: pointer;
    z-index: 1200;
}
.hamburger span {
    display: block;
    width: 26px;
    height: 3px;
    margin: 4px 0;
    background: var(--primary-color);
    border-radius: 2px;
    transition: 0.3s;
}

.mobile-nav {
    position: fixed;
    top: 60px;
    left: 0;
    width: 100vw;
    background: rgba(255, 255, 255, 0.85);
    box-shadow: 0 4px 16px rgba(0,0,0,0.08);
    z-index: 1100;
    padding: 24px 0 12px 0;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.3s ease;
}

.mobile-nav.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.mobile-nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 18px;
}
.mobile-nav a {
    color: var(--text-color);
    font-size: 18px;
    text-decoration: none;
    font-weight: 500;
    padding: 8px 0;
    transition: color 0.2s;
}
.mobile-nav a:hover {
    color: var(--primary-color);
}
@keyframes fadeInMobileNav {
    from { opacity: 0; transform: translateY(-20px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 576px) {
    header .container {
        justify-content: center;
        position: relative;
    }
    .logo-link {
        margin: 0 auto;
        display: flex;
        justify-content: center;
        flex: 1 1 100%;
    }
    .logo {
        width: 110px;
        margin: 0 auto;
        display: block;
    }
    .main-nav {
        display: none !important;
    }
    .hamburger {
        display: flex;
        position: absolute;
        right: 16px;
        top: 10px;
    }
    .mobile-nav {
        display: block;
    }
    .mobile-nav[aria-hidden="true"] {
        display: none;
    }
    
    .mobile-nav[aria-hidden="false"] {
        display: block;
    }
}