* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Microsoft YaHei', 'PingFang SC', sans-serif;
    background: linear-gradient(135deg, #1a0e0a 0%, #2c1810 50%, #0d1b2a 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.auth-container {
    display: flex;
    width: 920px;
    min-height: 560px;
    background: #fff;
    border-radius: 16px;
    overflow: hidden;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.5);
}

.auth-box {
    flex: 1;
    padding: 45px 40px;
    display: flex;
    flex-direction: column;
}

.auth-header { text-align: center; margin-bottom: 30px; }
.auth-header h1 { font-size: 30px; color: #5D4037; margin-bottom: 8px; font-weight: 700; letter-spacing: 4px; }
.auth-header p { color: #8D6E63; font-size: 14px; letter-spacing: 2px; }

.tab-buttons { display: flex; gap: 10px; margin-bottom: 25px; }
.tab-btn {
    flex: 1; padding: 12px; border: 2px solid #D7CCC8; background: #fff;
    color: #8D6E63; font-size: 15px; cursor: pointer; border-radius: 8px;
    transition: all 0.3s ease; font-weight: 500;
}
.tab-btn:hover { background: #EFEBE9; border-color: #BCAAA4; }
.tab-btn.active { background: linear-gradient(135deg, #5D4037 0%, #3E2723 100%); color: #D4AF37; border-color: #5D4037; }

.auth-form { display: none; flex-direction: column; gap: 18px; }
.auth-form.active { display: flex; }

.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-group label { font-size: 13px; color: #5D4037; font-weight: 500; }
.form-group input {
    padding: 12px 15px; border: 1px solid #D7CCC8; border-radius: 8px;
    font-size: 14px; transition: all 0.3s ease; background: #FAFAFA;
}
.form-group input:focus { outline: none; border-color: #8D6E63; box-shadow: 0 0 0 3px rgba(93, 64, 55, 0.1); background: #fff; }

.submit-btn {
    padding: 14px; background: linear-gradient(135deg, #5D4037 0%, #3E2723 100%);
    color: #D4AF37; border: none; border-radius: 8px; font-size: 16px;
    font-weight: 600; cursor: pointer; transition: all 0.3s ease;
    margin-top: 10px; letter-spacing: 4px;
}
.submit-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(62, 39, 35, 0.4); }
.submit-btn:active { transform: translateY(0); }

.message { margin-top: 15px; padding: 10px; border-radius: 6px; text-align: center; font-size: 14px; display: none; }
.message.success { display: block; background: #E8F5E9; color: #2E7D32; border: 1px solid #C8E6C9; }
.message.error { display: block; background: #FFEBEE; color: #C62828; border: 1px solid #FFCDD2; }

.auth-bg {
    width: 400px;
    background: linear-gradient(135deg, #1565C0 0%, #0D47A1 50%, #01579B 100%);
    display: flex; align-items: center; justify-content: center;
    position: relative; overflow: hidden;
}

.auth-bg::before {
    content: ''; position: absolute; inset: 0;
    background: repeating-linear-gradient(0deg, transparent, transparent 20px, rgba(255,255,255,0.03) 20px, rgba(255,255,255,0.03) 21px),
                repeating-linear-gradient(90deg, transparent, transparent 20px, rgba(255,255,255,0.03) 20px, rgba(255,255,255,0.03) 21px);
}

.auth-bg::after {
    content: ''; position: absolute; bottom: 0; left: 0; right: 0; height: 120px;
    background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1200 120'%3E%3Cpath d='M0,60 C200,120 400,0 600,60 C800,120 1000,0 1200,60 L1200,120 L0,120 Z' fill='rgba(255,255,255,0.08)'/%3E%3C/svg%3E") repeat-x;
    background-size: 600px 120px;
    animation: waveMove 8s linear infinite;
}

@keyframes waveMove { 0% { background-position-x: 0; } 100% { background-position-x: 600px; } }

.bg-text { text-align: center; color: #fff; z-index: 1; padding: 0 30px; }
.bg-text h2 { font-size: 30px; margin-bottom: 15px; text-shadow: 2px 2px 8px rgba(0,0,0,0.3); letter-spacing: 4px; }
.bg-text p { font-size: 16px; opacity: 0.85; letter-spacing: 2px; }

@media (max-width: 900px) {
    .auth-container { flex-direction: column; width: 95%; max-width: 450px; }
    .auth-bg { width: 100%; height: 150px; order: -1; }
    .bg-text h2 { font-size: 22px; }
}