/* Hamburger Menu Button */
.menu-btn {
    position: absolute;
    left: 20px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
    z-index: 1001;
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.menu-btn span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: #333;
    transition: all 0.3s;
    border-radius: 2px;
}

.menu-btn:hover span {
    background-color: #e74c3c;
}

/* Side Menu */
.side-menu {
    position: fixed;
    left: -320px;
    top: 0;
    width: 320px;
    height: 100vh;
    background: white;
    box-shadow: 2px 0 10px rgba(0,0,0,0.1);
    z-index: 1002;
    transition: left 0.3s ease;
    overflow-y: auto;
}

.side-menu.active {
    left: 0;
}

.menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    background: rgba(0,0,0,0.5);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.menu-overlay.active {
    opacity: 1;
    visibility: visible;
}

.menu-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 2px solid #eee;
}

.menu-header h2 {
    margin: 0;
    color: #333;
    font-size: 24px;
}

.close-btn {
    background: none;
    border: none;
    font-size: 32px;
    cursor: pointer;
    color: #666;
    padding: 0;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.2s;
}

.close-btn:hover {
    color: #e74c3c;
}

.menu-nav {
    padding: 10px 0;
}

.menu-nav a {
    display: flex;
    align-items: center;
    padding: 15px 20px;
    color: #333;
    text-decoration: none;
    transition: background 0.2s;
    font-size: 16px;
    gap: 12px;
}

.menu-nav a:hover {
    background: #f5f5f5;
}

.menu-icon {
    font-size: 20px;
    width: 24px;
    text-align: center;
}

.menu-arrow {
    margin-left: auto;
    transition: transform 0.3s;
    font-size: 12px;
}

.menu-nav a.expanded .menu-arrow {
    transform: rotate(90deg);
}

/* Era Submenu */
.era-submenu {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background: #f9f9f9;
}

.era-submenu.expanded {
    max-height: 800px;
}

.era-submenu a {
    padding-left: 56px;
    font-size: 14px;
    color: #555;
}

.era-submenu a:hover {
    background: #eee;
}

/* Header adjustment for menu button */
header {
    position: relative;
}

header h1 {
    text-align: center;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .side-menu {
        width: 280px;
        left: -280px;
    }
    
    .menu-btn {
        left: 10px;
    }
}