/* 网站页眉 */
.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 80px;
    background-color: var(--bg-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 9%;
    box-sizing: border-box;
    z-index: 2001;
    transition: background-color 0.3s;
    font-family: 'Noto Serif SC', "Source Han Serif SC", "Source Han Serif CN", serif;
}

@media (max-width: 1600px) {
    .site-header {
        padding: 0 24px;
    }
}

@media (max-width: 768px) {
    .site-header {
        height: 60px;
        padding: 0 16px;
    }
    .site-name {
        font-size: 18px;
    }
    .site-url {
        font-size: 10px;
    }
}

.header-left {
    display: flex;
    flex-direction: column;
}

.site-name {
    font-size: 20px;
    font-weight: 900;
    color: var(--text-color);
    text-decoration: none;
    letter-spacing: 1px;
    transition: color 0.3s;
}

.site-url {
    font-size: 12px;
    color: var(--author-color);
    text-decoration: none;
    margin-top: -4px;
    transition: color 0.3s;
}

.header-right {
    position: relative;
}

.menu-icon {
    width: 24px;
    height: 18px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    cursor: pointer;
    padding: 10px;
    box-sizing: content-box;
    transition: transform 0.3s ease;
}

.menu-icon span {
    display: block;
    height: 2px;
    width: 100%;
    background-color: var(--text-color);
    border-radius: 2px;
    transition: background-color 0.3s;
}

/* 全屏遮罩菜单 */
.menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.4s ease, visibility 0.4s ease;
}

.menu-overlay::before {
    content: '';
    position: absolute;
    inset: 0;
    background-color: var(--bg-color);
    opacity: 0.97;
    z-index: -1;
    transition: background-color 0.3s;
}

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

.menu-overlay-links {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 1;
    transition: opacity 0.35s ease;
}

.menu-overlay-link {
    color: var(--text-color);
    text-decoration: none;
    font-size: 36px;
    font-weight: 900;
    font-family: 'Noto Serif SC', "Source Han Serif SC", "Source Han Serif CN", serif;
    letter-spacing: 0px;
    cursor: pointer;
    border: none;
    background: none;
    padding: 8px 0;
    transition: opacity 0.3s, transform 0.3s;
    position: relative;
}

.menu-overlay-link:hover {
    color: #5D8DAB;
    transform: scale(1.05);
}

.menu-overlay-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%) scaleX(0);
    width: 100%;
    height: 2px;
    background-color: var(--text-color);
    transition: transform 0.3s ease;
}

.menu-overlay-link:hover::after {
    transform: translateX(-50%) scaleX(1);
    background-color: #5D8DAB;
}

/* 遮罩中的圆形操作按钮（主题切换、操作提示） */
.menu-overlay-actions {
    display: flex;
    flex-direction: row;
    gap: 20px;
    margin-top: 48px;
}

.menu-overlay-action {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 1.5px solid var(--divider-color);
    background: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    transition: border-color 0.3s, background-color 0.3s, transform 0.3s;
}

.menu-overlay-action:hover {
    border-color: var(--text-color);
    transform: scale(1.08);
}

.menu-overlay-action svg {
    width: 20px;
    height: 20px;
    color: var(--text-color);
    transition: color 0.3s;
}

/* 关闭按钮 */
.menu-overlay-close {
    position: absolute;
    top: 30px;
    right: 40px;
    width: 40px;
    height: 40px;
    cursor: pointer;
    background: none;
    border: none;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.menu-overlay-close::before,
.menu-overlay-close::after {
    content: '';
    position: absolute;
    width: 28px;
    height: 2px;
    background-color: var(--text-color);
    transition: background-color 0.3s;
}

.menu-overlay-close::before {
    transform: rotate(45deg);
}

.menu-overlay-close::after {
    transform: rotate(-45deg);
}

.menu-overlay-close:hover::before,
.menu-overlay-close:hover::after {
    background-color: var(--author-color);
}

/* 菜单内的快捷操作面板（替代弹窗） */
.menu-overlay-shortcut {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 15px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.35s ease, visibility 0.35s ease;
}

.menu-overlay.shortcut-mode .menu-overlay-links {
    opacity: 0;
    pointer-events: none;
}

.menu-overlay.shortcut-mode .menu-overlay-shortcut {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.menu-overlay-shortcut .shortcut-title {
    font-size: 28px;
    font-weight: 900;
    color: var(--text-color);
    margin-bottom: 15px;
}

.menu-overlay-shortcut .shortcut-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
    width: 300px;
}

.menu-overlay-shortcut .shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--divider-color);
}

.menu-overlay-shortcut .shortcut-desc {
    font-size: 16px;
    color: var(--text-color);
}

.menu-overlay-shortcut kbd.shortcut-key {
    background-color: var(--card-bg);
    padding: 4px 10px;
    border-radius: 4px;
    border: 1px solid var(--divider-color);
    font-family: monospace;
    font-weight: 700;
    color: var(--text-color);
    min-width: 24px;
    text-align: center;
    font-size: 14px;
}

.menu-overlay-shortcut .shortcut-back {
    margin-top: 30px;
    padding: 10px 28px;
    background-color: var(--text-color);
    color: var(--bg-color);
    border: none;
    border-radius: 4px;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    font-family: inherit;
    transition: opacity 0.2s;
}

.menu-overlay-shortcut .shortcut-back:hover {
    opacity: 0.85;
}

@media (max-width: 768px) {
    .menu-overlay-shortcut .shortcut-title {
        font-size: 22px;
    }
    .menu-overlay-shortcut .shortcut-list {
        width: 260px;
    }
    .menu-overlay-shortcut .shortcut-desc {
        font-size: 14px;
    }
}

/* 汉堡图标动画 */
.menu-icon.active span:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.menu-icon.active span:nth-child(2) {
    opacity: 0;
}

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

.menu-icon span {
    transition: transform 0.3s ease, opacity 0.3s ease;
}

@media (max-width: 768px) {
    .menu-overlay-link {
        font-size: 26px;
        letter-spacing: 0px;
    }

    .menu-overlay-links {
        gap: 24px;
    }

    .menu-overlay-close {
        top: 16px;
        right: 20px;
    }

    #shortcut-toggle-btn {
        display: none;
    }
}

/* 快捷键提示弹窗 */
.shortcut-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: all 0.3s;
}

.shortcut-modal.active {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.shortcut-content {
    background-color: var(--bg-color);
    padding: 40px;
    border-radius: 16px;
    max-width: 400px;
    width: 90%;
    box-shadow: 0 20px 50px rgba(0,0,0,0.3);
    font-family: 'Noto Serif SC', "Source Han Serif SC", "Source Han Serif CN", serif;
}

.shortcut-title {
    font-size: 24px;
    font-weight: 900;
    margin-bottom: 25px;
    text-align: center;
}

.shortcut-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.shortcut-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    border-bottom: 1px solid var(--divider-color);
}

.shortcut-desc {
    font-size: 14px;
    color: var(--text-muted);
}

kbd.shortcut-key {
    background-color: var(--card-bg);
    padding: 4px 8px;
    border-radius: 4px;
    border: 1px solid var(--divider-color);
    font-family: monospace;
    font-weight: 700;
    color: var(--text-color);
    min-width: 20px;
    text-align: center;
}

.shortcut-close {
    margin-top: 30px;
    width: 100%;
    padding: 12px;
    background-color: var(--text-color);
    color: var(--bg-color);
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s;
}

.shortcut-close:hover {
    transform: scale(1.02);
}