* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Segoe UI', system-ui, -apple-system, sans-serif; }

/* ========== 登录页（保留） ========== */
.login-body {
    min-height: 100vh;
    background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 50%, #4f46e5 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    animation: bgShift 8s ease infinite;
    background-size: 200% 200%;
}
@keyframes bgShift {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}
.login-container { width: 100%; max-width: 440px; padding: 20px; }
.login-card {
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(16px);
    border-radius: 24px;
    padding: 48px 40px;
    box-shadow: 0 30px 60px rgba(0,0,0,0.5);
    animation: floatUp 0.6s ease;
}
@keyframes floatUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
.login-header { text-align: center; margin-bottom: 36px; }
.logo-icon { font-size: 56px; margin-bottom: 10px; }
.login-header h1 { font-size: 28px; font-weight: 700; color: #1e293b; margin-bottom: 8px; }
.login-header p { color: #64748b; font-size: 16px; }
.alert-error { background: #fee2e2; color: #dc2626; padding: 12px 16px; border-radius: 12px; margin-bottom: 24px; font-size: 14px; font-weight: 500; }
.form-group { margin-bottom: 24px; }
.form-group label { display: block; margin-bottom: 8px; font-weight: 600; color: #334155; font-size: 14px; }
.form-group input {
    width: 100%; padding: 14px 18px; border: 2px solid #e2e8f0;
    border-radius: 14px; font-size: 16px; transition: all 0.3s; background: #f8fafc;
}
.form-group input:focus { outline: none; border-color: #4f46e5; background: #fff; box-shadow: 0 0 0 4px rgba(79,70,229,0.2); }
.btn {
    display: inline-block; padding: 14px 28px; border: none; border-radius: 14px;
    font-size: 16px; font-weight: 600; cursor: pointer; transition: all 0.3s; text-align: center;
}
.btn-primary { background: linear-gradient(135deg, #4f46e5, #7c3aed); color: #fff; width: 100%; box-shadow: 0 8px 20px rgba(79,70,229,0.4); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 24px rgba(79,70,229,0.5); }
.btn-block { width: 100%; }

/* ========== 用户端内部布局 ========== */
.user-body {
    display: flex;
    min-height: 100vh;
    background: #f1f5f9;
}
/* 侧边栏 */
.user-sidebar {
    width: 250px;
    background: linear-gradient(180deg, #ffffff, #f8fafc);
    border-right: 1px solid #e2e8f0;
    box-shadow: 2px 0 10px rgba(0,0,0,0.05);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 100;
}
.sidebar-brand {
    padding: 24px 20px;
    border-bottom: 1px solid #e2e8f0;
}
.sidebar-brand h2 {
    font-size: 20px;
    color: #1e293b;
    margin: 0;
}
.sidebar-nav {
    flex: 1;
    padding: 12px 0;
    overflow-y: auto;
}
.nav-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px 20px;
    color: #475569;
    text-decoration: none;
    font-weight: 500;
    font-size: 15px;
    transition: all 0.2s;
    border-left: 3px solid transparent;
    margin-bottom: 2px;
}
.nav-item:hover {
    background: #f1f5f9;
    color: #1e293b;
}
.nav-item.active {
    background: #eef2ff;
    color: #4338ca;
    border-left-color: #4f46e5;
    font-weight: 600;
}
.nav-icon { font-size: 18px; }
.nav-divider {
    height: 1px;
    background: #e2e8f0;
    margin: 12px 20px;
}
.nav-logout {
    margin-top: auto;
    color: #ef4444;
}
.nav-logout:hover {
    background: #fef2f2;
    color: #dc2626;
}

/* 主内容区 */
.main-content {
    margin-left: 250px;
    flex: 1;
    padding: 32px;
    width: calc(100% - 250px);
}
.page-header {
    margin-bottom: 32px;
}
.page-header h1 {
    font-size: 26px;
    color: #1e293b;
    font-weight: 700;
}

/* 占位卡片 */
.placeholder-card {
    background: white;
    border-radius: 24px;
    padding: 60px 40px;
    text-align: center;
    box-shadow: 0 15px 30px rgba(0,0,0,0.05);
    max-width: 600px;
    margin: 0 auto;
}
.placeholder-icon {
    font-size: 64px;
    margin-bottom: 20px;
}
.placeholder-card h2 {
    font-size: 24px;
    color: #1e293b;
    margin-bottom: 12px;
}
.placeholder-card p {
    color: #64748b;
    font-size: 16px;
}

/* 响应式调整 */
@media (max-width: 768px) {
    .user-sidebar {
        width: 200px;
    }
    .main-content {
        margin-left: 200px;
        width: calc(100% - 200px);
        padding: 20px;
    }
}