/* ===================================================================
   Header 專屬樣式表 (assets/header.css)
   =================================================================== */

/* -------------------------------------------------------------------
 * 01. 網站頁首 (Main Header)
 * ------------------------------------------------------------------- */
.main-header {
    background-color: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 0.75rem 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease-in-out;
}

.main-header.scrolled {
    border-bottom-color: var(--border-color);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    /* .container class is required on the parent element */
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.logo a {
    display: inline-block;
}

.logo-image {
    height: 45px;
    width: auto;
    display: block;
}

/* 桌面版導覽列 */
.main-nav-desktop {
    display: flex;
    gap: 1rem;
}

.nav-link {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    position: relative;
    transition: color 0.3s;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s;
}

.nav-link:hover {
    color: var(--primary-color);
}

.nav-link:hover::after {
    width: 100%;
}

.nav-link.active {
    color: var(--primary-color);
}

/* -------------------------------------------------------------------
 * 02. 行動版導覽列與漢堡選單 (Mobile Navigation)
 * ------------------------------------------------------------------- */
.header-tools {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.hamburger-btn {
    color:#000;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    z-index: 1002;
    height: 30px;
    width: 30px;
    display: none; /* 預設隱藏，由 RWD 控制顯示 */
    flex-direction: column;
    justify-content: space-around;
}

.hamburger-btn span {
    display: block;
    width: 100%;
    height: 3px;
    background-color: var(--dark-color);
    border-radius: 3px;
    transition: all 0.3s ease-in-out;
}

.mobile-nav-menu {
    position: fixed;
    top: 0;
    right: 0;
    width: 80%;
    max-width: 320px;
    height: 100%;
    background-color: #fff;
    box-shadow: -5px 0 15px rgba(0, 0, 0, 0.1);
    z-index: 1002;
    transform: translateX(100%);
    transition: transform 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    display: flex;
    flex-direction: column;
}

.mobile-nav-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.mobile-menu-title {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--dark-color);
}

.close-btn {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-muted);
    cursor: pointer;
    line-height: 1;
}

.mobile-nav-links {
    padding: 1.5rem 0;
    flex-grow: 1;
    overflow-y: auto;
    background-color: var(--paper);
    color: var(--text-color);
}

.mobile-nav-links .nav-link {
    display: flex;
    align-items: center;
    padding: 1rem 1.5rem;
    font-size: 1.1rem;
    font-weight: 500;
    border-bottom: 1px solid var(--border-color);
    position: relative;
    z-index: 1003;
    cursor: pointer;
    color: var(--text-color);
}

.mobile-nav-links .nav-link:last-child {
    border-bottom: none;
}

.menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.4s, visibility 0.4s;
}

/* 當選單開啟時的 Body 狀態 */
body.menu-open {
    overflow: hidden;
}

body.menu-open .mobile-nav-menu {
    transform: translateX(0);
}

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

/* -------------------------------------------------------------------
 * 03. Header 響應式設計 (Responsive)
 * ------------------------------------------------------------------- */
@media (max-width: 992px) {
    .header-content {
        position: relative;
        justify-content: center;
    }
    .header-tools {
        position: absolute;
        right: 1.5rem; /* Match .container padding */
        top: 50%;
        transform: translateY(-50%);
        z-index: 1001;
    }
    .main-nav-desktop {
        display: none;
    }
    .hamburger-btn {
        display: flex;
    }
}