:root { --primary: #6366f1; --bg: #f8fafc; --text: #1e293b; --text-secondary: #64748b; --border: #e2e8f0; --danger: #ef4444; }
* { margin: 0; padding: 0; box-sizing: border-box; }
body { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif; min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 20px; }
.login-container { background: white; border-radius: 20px; padding: 40px 30px; width: 100%; max-width: 400px; box-shadow: 0 20px 60px rgba(0,0,0,0.15); }
.login-header { text-align: center; margin-bottom: 30px; }
.login-header .logo { font-size: 48px; margin-bottom: 10px; }
.login-header h1 { font-size: 24px; color: var(--text); margin-bottom: 5px; }
.login-header p { font-size: 13px; color: var(--text-secondary); }
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 13px; font-weight: 600; color: var(--text); margin-bottom: 6px; }
.form-group input { width: 100%; height: 44px; border: 1.5px solid var(--border); border-radius: 10px; padding: 0 14px; font-size: 14px; color: var(--text); background: #f8fafc; outline: none; transition: border-color 0.3s; }
.form-group input:focus { border-color: var(--primary); background: white; }
.login-btn { width: 100%; height: 46px; background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%); color: white; border: none; border-radius: 10px; font-size: 16px; font-weight: 600; cursor: pointer; margin-top: 8px; }
.login-btn:disabled { opacity: 0.6; cursor: not-allowed; }
.loading-spinner { display: inline-block; width: 16px; height: 16px; border: 2px solid rgba(255,255,255,0.3); border-top-color: white; border-radius: 50%; animation: spin 0.6s linear infinite; vertical-align: middle; margin-right: 6px; }
@keyframes spin { to { transform: rotate(360deg); } }
.alert { padding: 12px 16px; border-radius: 10px; font-size: 13px; margin-bottom: 16px; display: none; }
.alert.show { display: block; }
.alert-error { background: #fef2f2; color: #dc2626; border: 1px solid #fecaca; }
.demo-info { margin-top: 24px; padding: 16px; background: #f8fafc; border-radius: 10px; border: 1px solid var(--border); }
.demo-info h4 { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; }
.demo-info p { font-size: 11px; color: var(--text-secondary); line-height: 1.8; }
.demo-info code { background: #eef2ff; color: var(--primary); padding: 1px 6px; border-radius: 4px; font-size: 11px; }
@media (max-width: 360px) { .login-container { padding: 30px 20px; } }