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

body {
    font-family: 'Orbitron', 'Arial Black', sans-serif;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(180deg, #0a0a0a 0%, #1a0a2e 50%, #16213e 100%);
}

/* 返回按钮 */
.back-button {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: rgba(0, 255, 255, 0.1);
    border: 2px solid #00ffff;
    border-radius: 6px;
    color: #00ffff;
    text-decoration: none;
    font-size: 14px;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 0 20px rgba(0, 255, 255, 0.3);
    text-transform: uppercase;
}

.back-button:hover {
    background: rgba(0, 255, 255, 0.2);
    box-shadow: 0 0 30px rgba(0, 255, 255, 0.5);
    transform: translateY(-2px);
}

/* 赛博城市背景 */
.cyber-city-background {
    position: fixed;
    width: 100vw;
    height: 100vh;
    top: 0;
    left: 0;
    z-index: -1;
}

/* 城市天际线 */
.city-skyline {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 60%;
    display: flex;
    align-items: flex-end;
    justify-content: space-around;
}

.building {
    background: linear-gradient(180deg, #1a1a2e 0%, #16213e 100%);
    border: 1px solid rgba(0, 255, 255, 0.3);
    position: relative;
    animation: buildingGlow 4s ease-in-out infinite alternate;
}

.building::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: repeating-linear-gradient(
        0deg,
        transparent 0px,
        transparent 8px,
        rgba(0, 255, 255, 0.1) 8px,
        rgba(0, 255, 255, 0.1) 10px
    );
}

.building-1 { width: 60px; height: 200px; animation-delay: 0s; }
.building-2 { width: 80px; height: 250px; animation-delay: 0.5s; }
.building-3 { width: 70px; height: 180px; animation-delay: 1s; }
.building-4 { width: 90px; height: 280px; animation-delay: 1.5s; }
.building-5 { width: 65px; height: 220px; animation-delay: 2s; }
.building-6 { width: 75px; height: 190px; animation-delay: 2.5s; }

@keyframes buildingGlow {
    0% { box-shadow: 0 0 10px rgba(0, 255, 255, 0.2); }
    100% { box-shadow: 0 0 30px rgba(0, 255, 255, 0.5); }
}

/* 霓虹招牌 */
.neon-signs {
    position: absolute;
    width: 100%;
    height: 100%;
}

.neon-sign {
    position: absolute;
    color: #ff0080;
    font-size: 20px;
    font-weight: 900;
    text-transform: uppercase;
    letter-spacing: 2px;
    text-shadow: 
        0 0 5px #ff0080,
        0 0 10px #ff0080,
        0 0 15px #ff0080,
        0 0 20px #ff0080;
    animation: neonFlicker 3s ease-in-out infinite;
}

.sign-1 {
    top: 30%;
    left: 15%;
    animation-delay: 0s;
}

.sign-2 {
    top: 45%;
    right: 20%;
    color: #00ff80;
    text-shadow: 
        0 0 5px #00ff80,
        0 0 10px #00ff80,
        0 0 15px #00ff80,
        0 0 20px #00ff80;
    animation-delay: 1s;
}

.sign-3 {
    bottom: 40%;
    left: 50%;
    transform: translateX(-50%);
    color: #ffff00;
    text-shadow: 
        0 0 5px #ffff00,
        0 0 10px #ffff00,
        0 0 15px #ffff00,
        0 0 20px #ffff00;
    animation-delay: 2s;
}

@keyframes neonFlicker {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
    75% { opacity: 0.9; }
}

/* 飞行汽车 */
.flying-cars {
    position: absolute;
    width: 100%;
    height: 100%;
}

.flying-car {
    position: absolute;
    font-size: 16px;
    filter: drop-shadow(0 0 10px #00ffff);
    animation: flyAcross 8s linear infinite;
}

.car-1 {
    top: 25%;
    left: -50px;
    animation-delay: 0s;
}

.car-2 {
    top: 40%;
    left: -50px;
    animation-delay: 3s;
}

.car-3 {
    top: 55%;
    left: -50px;
    animation-delay: 6s;
}

@keyframes flyAcross {
    0% { left: -50px; }
    100% { left: calc(100% + 50px); }
}

/* 全息广告 */
.hologram-ads {
    position: absolute;
    width: 100%;
    height: 100%;
}

.hologram {
    position: absolute;
    font-size: 24px;
    color: rgba(0, 255, 255, 0.7);
    filter: drop-shadow(0 0 15px #00ffff);
    animation: hologramFloat 4s ease-in-out infinite;
}

.ad-1 {
    top: 20%;
    right: 15%;
    animation-delay: 0s;
}

.ad-2 {
    top: 60%;
    left: 10%;
    animation-delay: 1.5s;
}

.ad-3 {
    bottom: 25%;
    right: 30%;
    animation-delay: 3s;
}

@keyframes hologramFloat {
    0%, 100% { transform: translateY(0) scale(1); opacity: 0.7; }
    50% { transform: translateY(-20px) scale(1.1); opacity: 1; }
}

/* 雨滴效果 */
.rain-effect {
    position: absolute;
    width: 100%;
    height: 100%;
}

.rain-drop {
    position: absolute;
    width: 2px;
    height: 20px;
    background: linear-gradient(180deg, transparent 0%, rgba(0, 255, 255, 0.6) 100%);
    animation: rainFall 1.5s linear infinite;
}

.drop-1 { left: 20%; animation-delay: 0s; }
.drop-2 { left: 40%; animation-delay: 0.3s; }
.drop-3 { left: 60%; animation-delay: 0.6s; }
.drop-4 { left: 80%; animation-delay: 0.9s; }
.drop-5 { left: 30%; animation-delay: 1.2s; }

@keyframes rainFall {
    0% { top: -20px; opacity: 0; }
    10% { opacity: 1; }
    90% { opacity: 1; }
    100% { top: 100vh; opacity: 0; }
}

/* 表单容器 */
.login-container {
    width: 100%;
    max-width: 400px;
    padding: 20px;
    z-index: 100;
}

.form-container.hidden {
    display: none;
}

/* 赛博卡片 */
.cyber-card {
    background: rgba(10, 10, 10, 0.9);
    border: 2px solid #00ffff;
    border-radius: 10px;
    padding: 40px 30px;
    box-shadow: 
        0 0 30px rgba(0, 255, 255, 0.3),
        inset 0 0 20px rgba(0, 255, 255, 0.1);
    backdrop-filter: blur(15px);
    position: relative;
    overflow: hidden;
}

.cyber-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, transparent, #00ffff, transparent);
    animation: scanLine 4s linear infinite;
}

@keyframes scanLine {
    0% { left: -100%; }
    100% { left: 100%; }
}

.card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 10px;
}

.status-led {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: #00ff80;
    box-shadow: 0 0 15px #00ff80;
    animation: ledPulse 2s ease-in-out infinite;
}

.status-led.register-mode {
    background: #ff0080;
    box-shadow: 0 0 15px #ff0080;
}

.status-led.reset-mode {
    background: #ffff00;
    box-shadow: 0 0 15px #ffff00;
}

@keyframes ledPulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

.signal-bars {
    display: flex;
    gap: 3px;
    align-items: flex-end;
}

.bar {
    width: 4px;
    background: #00ffff;
    border-radius: 2px;
    animation: signalStrength 2s ease-in-out infinite;
}

.bar-1 { height: 8px; animation-delay: 0s; }
.bar-2 { height: 12px; animation-delay: 0.2s; }
.bar-3 { height: 16px; animation-delay: 0.4s; }
.bar-4 { height: 20px; animation-delay: 0.6s; }

@keyframes signalStrength {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 1; }
}

.cyber-card h2 {
    color: #00ffff;
    font-size: 24px;
    font-weight: 900;
    text-align: center;
    margin: 0;
    text-shadow: 0 0 10px rgba(0, 255, 255, 0.5);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.subtitle {
    color: #ff0080;
    text-align: center;
    margin-bottom: 30px;
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* 表单样式 */
.form-group {
    position: relative;
    margin-bottom: 25px;
}

.form-group input {
    width: 100%;
    padding: 15px 0;
    background: transparent;
    border: none;
    border-bottom: 2px solid rgba(0, 255, 255, 0.3);
    color: #ffffff;
    font-size: 16px;
    font-family: 'Orbitron', monospace;
    outline: none;
    transition: all 0.3s ease;
}

.form-group input:focus {
    border-bottom-color: #00ffff;
    box-shadow: 0 2px 10px rgba(0, 255, 255, 0.3);
}

.form-group label {
    position: absolute;
    top: 15px;
    left: 0;
    color: rgba(255, 255, 255, 0.6);
    font-size: 16px;
    pointer-events: none;
    transition: all 0.3s ease;
    font-family: 'Orbitron', monospace;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.form-group input:focus + label,
.form-group input:valid + label {
    top: -10px;
    font-size: 12px;
    color: #00ffff;
}

.neon-underline {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #00ffff, #ff0080);
    transition: width 0.3s ease;
    box-shadow: 0 0 10px rgba(0, 255, 255, 0.5);
}

.form-group input:focus ~ .neon-underline {
    width: 100%;
}

/* 按钮样式 */
.login-btn {
    width: 100%;
    padding: 15px;
    background: linear-gradient(45deg, rgba(0, 255, 255, 0.1), rgba(255, 0, 128, 0.1));
    border: 2px solid #00ffff;
    border-radius: 6px;
    color: #00ffff;
    font-size: 16px;
    font-weight: 700;
    font-family: 'Orbitron', monospace;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: all 0.3s ease;
    margin: 20px 0;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.login-btn:hover {
    background: linear-gradient(45deg, rgba(0, 255, 255, 0.2), rgba(255, 0, 128, 0.2));
    box-shadow: 0 0 25px rgba(0, 255, 255, 0.4);
    transform: translateY(-2px);
}

.btn-glow {
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0, 255, 255, 0.4), transparent);
    transition: left 0.5s ease;
}

.login-btn:hover .btn-glow {
    left: 100%;
}

/* 验证码组 */
.verification-group {
    display: flex;
    align-items: flex-end;
    gap: 10px;
}

.verification-group input {
    flex: 1;
}

.verify-btn {
    padding: 12px 16px;
    background: rgba(255, 0, 128, 0.1);
    border: 1px solid #ff0080;
    border-radius: 4px;
    color: #ff0080;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-family: 'Orbitron', monospace;
    text-transform: uppercase;
    white-space: nowrap;
    flex-shrink: 0;
}

.verify-btn:hover {
    background: rgba(255, 0, 128, 0.2);
    box-shadow: 0 0 15px rgba(255, 0, 128, 0.3);
    transform: translateY(-2px);
}

/* 附加链接 */
.additional-links {
    text-align: center;
    margin-top: 20px;
}

.cyber-link {
    color: #00ffff;
    text-decoration: none;
    font-size: 14px;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-family: 'Orbitron', monospace;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.cyber-link:hover {
    color: #ff0080;
    text-shadow: 0 0 10px rgba(255, 0, 128, 0.5);
}

.divider {
    color: rgba(255, 255, 255, 0.3);
    margin: 0 15px;
}

/* 响应式设计 */
@media (max-width: 480px) {
    .login-container {
        padding: 15px;
    }
    
    .cyber-card {
        padding: 30px 20px;
    }
    
    .back-button {
        top: 15px;
        left: 15px;
        padding: 10px 15px;
        font-size: 12px;
    }
    
    .building {
        width: 40px !important;
        height: 120px !important;
    }
    
    .neon-sign {
        font-size: 16px;
    }

    .verification-group {
        gap: 8px;
    }

    .verify-btn {
        padding: 10px 12px;
        font-size: 11px;
        min-width: 70px;
    }
}