* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    background: linear-gradient(135deg, var(--primary-color) 0%, #5a8bdb 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    padding: 20px;
    position: relative;
}

/* 登录页面主题切换按钮 */
.login-theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

.login-theme-toggle .btn-theme-toggle {
    margin-right: 0;
    background: rgba(255,255,255,0.2);
    color: #ffffff;
}

.login-theme-toggle .btn-theme-toggle:hover {
    background: rgba(255,255,255,0.3);
}

.theme-dark .login-theme-toggle .btn-theme-toggle {
    background: rgba(31,41,55,0.5);
}

.theme-dark .login-theme-toggle .btn-theme-toggle:hover {
    background: rgba(31,41,55,0.7);
}

/* 登录页面暗色主题渐变背景 */
.theme-dark body {
    background: linear-gradient(135deg, #1e3a5f 0%, #111827 100%);
}

/* 动态粒子背景画布 */
#particleCanvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
}
.login-box {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 420px;
    padding: 40px 30px;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.2);
    backdrop-filter: blur(10px);
    animation: slideUp 0.5s ease-out;
}
@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}
.login-header {
    text-align: center;
    margin-bottom: 35px;
}
.login-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color) 0%, #5a8bdb 100%);
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    box-shadow: 0 8px 20px rgba(59, 126, 234, 0.4);
}
.login-icon i {
    font-size: 40px;
    color: #fff;
}
.login-box h2 {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}
.login-subtitle {
    color: var(--text-secondary);
    font-size: 14px;
}
.login-box .mb-3 {
    margin-bottom: 20px;
    position: relative;
}
.login-box .form-control {
    height: 50px;
    padding: 12px 20px 12px 45px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 15px;
    transition: all 0.3s ease;
    position: relative;
    z-index: 1;
}
.login-box .form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(59, 126, 234, 0.1);
    outline: none;
}
.input-icon {
    position: absolute;
    left: 15px;
    top: 15px;
    color: var(--text-light);
    font-size: 18px;
    transition: color 0.3s ease;
    z-index: 10;
}
.mb-3:focus-within .input-icon {
    color: var(--primary-color);
}
.login-box .btn {
    width: 100%;
    padding: 14px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 10px;
    background: linear-gradient(135deg, var(--primary-color) 0%, #5a8bdb 100%);
    box-shadow: 0 6px 20px rgba(59, 126, 234, 0.4);
    transition: all 0.3s ease;
}
.login-box .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(59, 126, 234, 0.5);
    background: linear-gradient(135deg, var(--primary-hover) 0%, #4a7bcb 100%);
}
.login-box .btn:active {
    transform: translateY(0);
}
.alert {
    border-radius: 10px;
    border: none;
    padding: 15px 20px;
}
.alert i {
    margin-right: 8px;
}
.login-footer {
    text-align: center;
    margin-top: 30px;
    padding-top: 25px;
    border-top: 1px solid var(--border-color);
}
.login-footer small {
    color: var(--text-secondary);
    font-size: 13px;
}
.login-footer small strong {
    color: var(--primary-color);
    font-weight: 600;
}
@media (max-width: 480px) {
    .login-box {
        padding: 30px 20px;
    }
    .login-icon {
        width: 60px;
        height: 60px;
    }
    .login-icon i {
        font-size: 30px;
    }
    .login-box h2 {
        font-size: 24px;
    }
    .login-box .form-control {
        height: 45px;
        padding: 10px 15px 10px 40px;
    }
    .input-icon {
        left: 12px;
        top: 14px;
        font-size: 16px;
    }
    .login-box .btn {
        padding: 12px;
        font-size: 15px;
    }
}