/* ===== 侧边栏样式 ===== */
.sidebar-trigger {
    position: fixed;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 20px;
    height: 100px;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 0 12px 12px 0;
    z-index: 1000;
    cursor: pointer;
    transition: all var(--transition-speed) ease;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-left: none;
}

.sidebar-trigger:hover {
    width: 25px;
    background: rgba(255, 255, 255, 0.2);
}

.sidebar {
    position: fixed;
    left: -300px;
    top: 0;
    width: 280px;
    height: 100vh;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(30px);
    transition: left var(--transition-speed) var(--transition-bounce);
    z-index: 999;
    box-shadow: 4px 0 20px rgba(0, 0, 0, 0.1);
    border-right: 1px solid rgba(255, 255, 255, 0.3);
}

.sidebar-trigger:hover + .sidebar,
.sidebar:hover {
    left: 0;
}

.sidebar-header {
    padding: 30px 25px;
    background: var(--gradient-primary);
    color: var(--white);
    font-size: 1.3rem;
    font-weight: 600;
    text-align: center;
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.sidebar-content {
    padding: 20px 0;
}

.sidebar-item {
    display: block;
    padding: 15px 25px;
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition-speed) ease;
    border-left: 4px solid transparent;
    font-weight: 500;
}

.sidebar-item:hover {
    background: rgba(102, 126, 234, 0.1);
    border-left-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateX(8px);
}

.sidebar-item i {
    margin-right: 12px;
    width: 20px;
    text-align: center;
}

/* 主题切换按钮 */
.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-primary);
    transition: all var(--transition-speed);
    margin-right: 1rem;
}

.theme-toggle:hover {
    background: var(--primary-blue);
    color: var(--white);
    border-color: var(--primary-blue);
    transform: scale(1.1);
}

.theme-toggle i {
    font-size: 1rem;
    transition: transform var(--transition-speed);
}

[data-theme="dark"] .theme-toggle i:before {
    content: "\f185"; /* fa-sun */
}

/* 顶部公告栏 */
.site-announcement {
    width: 100%;
    padding: 0.6rem 1rem;
    background: linear-gradient(90deg, var(--primary-blue), var(--accent-teal));
    color: var(--white);
    border-bottom: 1px solid rgba(255,255,255,0.25);
    box-shadow: var(--box-shadow);
}
.announcement-content {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-size: 0.95rem;
}
.announcement-content .divider { opacity: 0.8; }
.announcement-content i { color: var(--white); }

/* 暗黑模式适配 */
body[data-theme="dark"] .site-announcement {
    background: linear-gradient(90deg, #0f172a, #1e293b);
    color: #e5e7eb;
    border-bottom: 1px solid #334155;
}
body[data-theme="dark"] .announcement-content i { color: #22d3ee; }

/* ===== 按钮组件样式 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.65rem 1rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition-speed);
    box-shadow: var(--box-shadow);
    backdrop-filter: blur(8px);
}

/* 暗黑模式按钮可读性增强 */
body[data-theme="dark"] .btn {
    color: #e5e7eb;
    border-color: #475569;
    box-shadow: none;
    background: rgba(2, 6, 23, 0.4);
}

/* feature-button暗黑模式增强 */
body[data-theme="dark"] .feature-button {
    background: rgba(30, 41, 59, 0.85);
    border-color: #475569;
    box-shadow: none;
}
body[data-theme="dark"] .feature-button .text {
    color: #e5e7eb;
}
body[data-theme="dark"] .feature-button .icon {
    color: #9ecaff;
}

/* 侧边栏暗黑模式增强 */
body[data-theme="dark"] .sidebar {
    background: rgba(2, 6, 23, 0.85);
    border-right: 1px solid #334155;
}
body[data-theme="dark"] .sidebar-item {
    color: #cbd5e1;
    border-left-color: transparent;
}
body[data-theme="dark"] .sidebar-item:hover {
    background: rgba(51, 65, 85, 0.65);
    color: #ffffff;
    border-left-color: #22d3ee;
}

/* 页头/页脚暗黑模式增强 */
body[data-theme="dark"] .dashboard-header {
    background: rgba(2, 6, 23, 0.5);
    border-bottom-color: #334155;
}
body[data-theme="dark"] .dashboard-footer {
    background: rgba(2, 6, 23, 0.4);
    color: #cbd5e1;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-login {
    background: var(--gradient-primary);
    color: var(--white);
    box-shadow: var(--box-shadow);
}

.btn-login:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-hover);
}

.btn-register {
    background: var(--gradient-secondary);
    color: var(--white);
    box-shadow: var(--box-shadow);
}

.btn-register:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-hover);
}

.btn-logout {
    background: var(--gradient-accent);
    color: var(--white);
    box-shadow: var(--box-shadow);
}

.btn-logout:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-hover);
}

/* ===== 功能按钮卡片样式 ===== */
.feature-button {
    color: var(--text-primary);
    text-decoration: none;
    background: rgba(255, 255, 255, 0.95);
    padding: 30px 25px;
    border-radius: var(--border-radius-lg);
    text-align: center;
    transition: all var(--transition-speed) var(--transition-bounce);
    box-shadow: var(--box-shadow);
    border: 1px solid rgba(255, 255, 255, 0.3);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 180px;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(20px);
}

.feature-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity var(--transition-speed) ease;
    z-index: -1;
}

.feature-button:hover::before {
    opacity: 0.1;
}

.feature-button:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--box-shadow-hover);
    border-color: rgba(102, 126, 234, 0.3);
}

.feature-button .icon {
    font-size: 3rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 15px;
    transition: all var(--transition-speed) ease;
}

.feature-button:hover .icon {
    background: var(--gradient-secondary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transform: scale(1.1);
}

.feature-button .text {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-primary);
    transition: all var(--transition-speed) ease;
    line-height: 1.4;
}

.feature-button:hover .text {
    color: var(--primary-color);
    transform: translateY(-2px);
}

/* 友情链接样式 */
.friends-links {
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 2rem;
}

.friends-title {
    text-align: center;
    color: var(--text-primary);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.friends-title i {
    color: var(--danger-red);
    animation: heartbeat 2s ease-in-out infinite;
}

@keyframes heartbeat {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.friends-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.friend-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    color: var(--text-primary);
    text-decoration: none;
    transition: all var(--transition-speed);
    font-weight: 500;
}

.friend-link:hover {
    background: var(--primary-blue);
    color: var(--white);
    transform: translateY(-2px);
    box-shadow: var(--box-shadow-hover);
    border-color: var(--primary-blue);
}

.friend-link i {
    font-size: 1.2rem;
    color: var(--primary-blue);
    transition: color var(--transition-speed);
}

.friend-link:hover i {
    color: var(--white);
}

.friend-link span {
    font-size: 0.9rem;
}

/* ===== 欢迎面板组件 ===== */
.welcome-panel {
    grid-column: 1 / -1; /* 占满整行 */
    background: rgba(255, 255, 255, 0.95);
    padding: 40px;
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: var(--box-shadow);
    backdrop-filter: blur(15px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    position: relative;
    overflow: hidden;
}

.welcome-panel::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0.05;
    z-index: 1;
}

.welcome-panel > * {
    position: relative;
    z-index: 2;
}

.welcome-panel h2 {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 15px;
    font-size: 2.2rem;
    font-weight: 700;
}

.welcome-panel p {
    color: var(--text-color);
    font-size: 1.1rem;
    margin-bottom: 25px;
}

.logged-in-grid {
    margin-top: 35px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 25px;
}