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

html {
    font-size: 16px;
}

body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
    min-height: 100vh;
    position: relative;
    overflow-x: hidden;
}

.container {
    width: 100%;
    margin: 0 auto;
    position: relative;
}

img {
    max-width: 100%;
    height: auto;
}

input, select, textarea, button {
    font-size: inherit;
}

/* 超大屏幕 (>1920px) */
@media screen and (min-width: 1921px) {
    .container {
        max-width: 1600px;
    }
    
    .logo {
        width: 280px;
        height: 160px;
    }
    
    .navbar {
        height: 160px;
    }
    
    .navbar-logo {
        height: 160px;
    }
    
    .navbar-logo .logo {
        width: 280px;
        height: 160px;
    }
    
    .buttons-section {
        height: 90px;
    }
    
    .register-container {
        max-width: 480px;
        padding: 35px;
    }
}

/* 大型桌面 (1440px - 1920px) */
@media screen and (min-width: 1441px) and (max-width: 1920px) {
    .container {
        max-width: 1400px;
    }
    
    .logo {
        width: 260px;
        height: 150px;
    }
    
    .navbar {
        height: 150px;
    }
    
    .navbar-logo {
        height: 150px;
    }
    
    .navbar-logo .logo {
        width: 260px;
        height: 150px;
    }
    
    .buttons-section {
        height: 85px;
    }
    
    .register-container {
        max-width: 450px;
        padding: 30px;
    }
}

/* 标准桌面 (1200px - 1440px) */
@media screen and (min-width: 1201px) and (max-width: 1440px) {
    .container {
        max-width: 1100px;
    }
    
    .logo {
        width: 240px;
        height: 140px;
    }
    
    .navbar {
        height: 140px;
        padding: 0 15px;
    }
    
    .navbar-logo {
        height: 140px;
    }
    
    .navbar-logo .logo {
        width: 240px;
        height: 140px;
    }
    
    .buttons-section {
        height: 80px;
    }
    
    .buttons-container {
        padding: 8px 25px;
        gap: 15px;
    }
    
    .btn {
        font-size: 16px;
        padding: 8px;
    }
    
    .register-container {
        max-width: 420px;
        padding: 28px;
    }
    
    .register-container h2 {
        margin-bottom: 25px;
    }
}

/* 小型桌面/平板横屏 (992px - 1200px) */
@media screen and (min-width: 993px) and (max-width: 1200px) {
    .container {
        max-width: 960px;
        padding: 0 15px;
    }
    
    .logo {
        width: 220px;
        height: 130px;
    }
    
    .navbar {
        height: 130px;
        padding: 0 15px;
    }
    
    .navbar-logo {
        height: 130px;
    }
    
    .navbar-logo .logo {
        width: 220px;
        height: 130px;
    }
    
    .buttons-section {
        height: 75px;
    }
    
    .buttons-container {
        padding: 6px 20px;
        gap: 12px;
    }
    
    .btn {
        font-size: 15px;
        padding: 6px;
    }
    
    .banner-item {
        max-width: 95%;
    }
    
    .register-section {
        padding: 15px;
    }
    
    .register-container {
        max-width: 400px;
        padding: 25px;
    }
    
    .register-container h2 {
        margin-bottom: 22px;
        font-size: 22px;
    }
    
    .form-group {
        margin-bottom: 16px;
    }
    
    .form-group input {
        padding: 10px;
        font-size: 15px;
    }
    
    .verification-group {
        margin-bottom: 16px;
    }
    
    .register-btn {
        padding: 12px;
        font-size: 16px;
        margin-top: 16px;
    }
}

/* 平板竖屏/大手机横屏 (768px - 992px) */
@media screen and (min-width: 769px) and (max-width: 992px) {
    .container {
        max-width: 750px;
        padding: 0 12px;
    }
    
    .logo {
        width: 200px;
        height: 120px;
    }
    
    .navbar {
        height: 120px;
        padding: 0 12px;
    }
    
    .navbar-logo {
        height: 120px;
    }
    
    .navbar-logo .logo {
        width: 200px;
        height: 120px;
    }
    
    .navbar-link {
        font-size: 14px;
        padding: 6px 12px;
    }
    
    .buttons-section {
        height: 70px;
    }
    
    .buttons-container {
        padding: 5px 15px;
        gap: 10px;
        border-radius: 8px;
    }
    
    .btn {
        font-size: 14px;
        padding: 5px;
    }
    
    .enter-website-btn {
        padding: 10px 20px;
        font-size: 14px;
    }
    
    .banner-section {
    }
    
    .banner-item {
        max-width: 95%;
        border-radius: 15px;
    }
    
    .banner-item img {
        border-radius: 15px;
    }
    
    .register-section {
        min-height: 500px;
        padding: 12px;
    }
    
    .register-container {
        max-width: 380px;
        padding: 22px;
        border-radius: 8px;
    }
    
    .register-container h2 {
        margin-bottom: 20px;
        font-size: 20px;
    }
    
    .form-group {
        margin-bottom: 14px;
    }
    
    .form-group input {
        padding: 10px;
        font-size: 14px;
    }
    
    .verification-group {
        margin-bottom: 14px;
        flex-direction: column;
        gap: 8px;
    }
    
    .verification-group > div {
        width: 100%;
    }
    
    .verification-group .captcha-display {
        flex: none;
    }
    
    .verification-group input {
        height: 40px;
    }
    
    .verification-group button,
    .verification-group #captchaText {
        height: 40px;
        font-size: 14px;
    }
    
    .captcha-container {
        flex-direction: column;
        gap: 8px;
    }
    
    .captcha-container input {
        width: 100%;
        height: 40px;
    }
    
    .captcha-container img,
    .captcha-container #captchaText {
        width: 100%;
        height: 40px;
    }
    
    .register-btn {
        padding: 12px;
        font-size: 15px;
        margin-top: 14px;
    }
    
    .agreement-group {
        font-size: 13px;
    }
    
    .remember-me {
        font-size: 13px;
    }
}

/* 手机横屏/小平板竖屏 (576px - 768px) */
@media screen and (min-width: 577px) and (max-width: 768px) {
    .container {
        max-width: 100%;
        padding: 0 10px;
    }
    
    .logo {
        width: 180px;
        height: 100px;
    }
    
    .navbar {
        height: 100px;
        padding: 0 10px;
    }
    
    .navbar-logo {
        height: 100px;
    }
    
    .navbar-logo .logo {
        width: 180px;
        height: 100px;
    }
    
    .navbar-link {
        font-size: 13px;
        padding: 5px 10px;
    }
    
    .buttons-section {
        height: 60px;
    }
    
    .buttons-container {
        padding: 4px 12px;
        gap: 8px;
        border-radius: 6px;
    }
    
    .btn {
        font-size: 12px;
        padding: 4px;
    }
    
    .enter-website-btn {
        padding: 8px 16px;
        font-size: 13px;
    }
    
    .banner-section {
    }
    
    .banner-item {
        max-width: 98%;
        border-radius: 12px;
    }
    
    .banner-item img {
        border-radius: 12px;
    }
    
    .register-section {
        min-height: auto;
        padding: 10px;
        align-items: flex-start;
        padding-top: 20px;
    }
    
    .register-container {
        max-width: 100%;
        padding: 18px;
        border-radius: 6px;
    }
    
    .register-container h2 {
        margin-bottom: 16px;
        font-size: 18px;
    }
    
    .form-group {
        margin-bottom: 12px;
    }
    
    .form-group input {
        padding: 10px;
        font-size: 14px;
    }
    
    .verification-group {
        margin-bottom: 12px;
        flex-direction: column;
        gap: 8px;
    }
    
    .verification-group > div {
        width: 100%;
    }
    
    .verification-group input {
        height: 40px;
    }
    
    .verification-group button,
    .verification-group #captchaText {
        height: 40px;
        font-size: 14px;
    }
    
    .captcha-container {
        flex-direction: column;
        gap: 8px;
    }
    
    .captcha-container input {
        width: 100%;
        height: 40px;
    }
    
    .captcha-container img,
    .captcha-container #captchaText {
        width: 100%;
        height: 40px;
    }
    
    .register-btn {
        padding: 12px;
        font-size: 14px;
        margin-top: 12px;
    }
    
    .agreement-group {
        font-size: 12px;
    }
    
    .agreement-group input {
        width: 16px;
        height: 16px;
    }
    
    .remember-me {
        font-size: 12px;
    }
    
    .remember-me input[type="checkbox"] {
        width: 16px;
        height: 16px;
    }
    
    .user-info {
        flex-direction: column;
        gap: 5px;
    }
}

/* 手机竖屏 (<576px) */
@media screen and (max-width: 576px) {
    .container {
        max-width: 100%;
        padding: 0 8px;
    }
    
    .logo {
        width: 140px;
        height: 80px;
    }
    
    .logo .placeholder {
        font-size: 14px;
    }
    
    .navbar {
        height: 80px;
        padding: 0 8px;
        flex-wrap: wrap;
    }
    
    .navbar-logo {
        height: 80px;
    }
    
    .navbar-logo .logo {
        width: 140px;
        height: 80px;
    }
    
    .navbar-links {
        gap: 10px;
    }
    
    .navbar-link {
        font-size: 12px;
        padding: 4px 8px;
    }
    
    .buttons-section {
        height: 50px;
    }
    
    .buttons-container {
        padding: 3px 10px;
        gap: 6px;
        border-radius: 5px;
    }
    
    .btn {
        font-size: 11px;
        padding: 3px;
    }
    
    .enter-website-btn {
        padding: 6px 12px;
        font-size: 12px;
    }
    
    .banner-section {
    }
    
    .banner-item {
        max-width: 100%;
        border-radius: 8px;
    }
    
    .banner-item img {
        border-radius: 8px;
    }
    
    .register-section {
        min-height: auto;
        padding: 8px;
        align-items: flex-start;
        padding-top: 15px;
    }
    
    .register-container {
        max-width: 100%;
        padding: 15px;
        border-radius: 6px;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    }
    
    .register-container h2 {
        margin-bottom: 12px;
        font-size: 16px;
    }
    
    .form-group {
        margin-bottom: 10px;
    }
    
    .form-group label {
        font-size: 13px;
        margin-bottom: 5px;
    }
    
    .form-group input {
        padding: 8px 10px;
        font-size: 14px;
    }
    
    .verification-group {
        margin-bottom: 10px;
        flex-direction: column;
        gap: 6px;
    }
    
    .verification-group > div {
        width: 100%;
    }
    
    .verification-group input {
        height: 38px;
        font-size: 14px;
    }
    
    .verification-group button,
    .verification-group #captchaText {
        height: 38px;
        font-size: 13px;
    }
    
    .verification-group label {
        font-size: 12px;
    }
    
    .captcha-container {
        flex-direction: column;
        gap: 6px;
    }
    
    .captcha-container input {
        width: 100%;
        height: 38px;
        font-size: 14px;
    }
    
    .captcha-container img,
    .captcha-container #captchaText {
        width: 100%;
        height: 38px;
        font-size: 14px;
    }
    
    .register-btn {
        padding: 10px;
        font-size: 14px;
        margin-top: 10px;
    }
    
    .agreement-group {
        font-size: 11px;
        gap: 4px;
    }
    
    .agreement-group input {
        width: 14px;
        height: 14px;
    }
    
    .remember-me {
        font-size: 12px;
        margin-bottom: 12px;
    }
    
    .remember-me input[type="checkbox"] {
        width: 14px;
        height: 14px;
    }
    
    .user-info {
        flex-direction: column;
        gap: 3px;
    }
    
    .user-info span {
        font-size: 12px;
    }
    
    .loading {
        font-size: 18px;
    }
    
    .success-message,
    .error-message.big {
        padding: 12px;
        font-size: 14px;
    }
    
    .step-content {
        margin-top: 15px;
    }
}

/* 极小手机 (<400px) */
@media screen and (max-width: 400px) {
    .logo {
        width: 120px;
        height: 70px;
    }
    
    .navbar {
        height: 70px;
    }
    
    .navbar-logo {
        height: 70px;
    }
    
    .navbar-logo .logo {
        width: 120px;
        height: 70px;
    }
    
    .navbar-link {
        font-size: 11px;
        padding: 3px 6px;
    }
    
    .navbar-links {
        gap: 6px;
    }
    
    .buttons-section {
        height: 45px;
    }
    
    .buttons-container {
        padding: 2px 8px;
        gap: 4px;
    }
    
    .btn {
        font-size: 10px;
    }
    
    .enter-website-btn {
        padding: 5px 10px;
        font-size: 11px;
    }
    
    .banner-section {
    }
    
    .register-section {
        padding-top: 10px;
    }
    
    .register-container {
        padding: 12px;
    }
    
    .register-container h2 {
        margin-bottom: 10px;
        font-size: 15px;
    }
    
    .form-group {
        margin-bottom: 8px;
    }
    
    .form-group input {
        padding: 8px;
        font-size: 13px;
    }
    
    .register-btn {
        padding: 8px;
        font-size: 13px;
        margin-top: 8px;
    }
    
    .agreement-group {
        font-size: 10px;
    }
}

/* 打印样式 */
@media print {
    .navbar,
    .buttons-section,
    .banner-section {
        display: none;
    }
    
    .register-section {
        min-height: auto;
    }
    
    .register-container {
        box-shadow: none;
        border: 1px solid #ccc;
    }
}

/* 高对比度模式支持 */
@media (prefers-contrast: high) {
    .form-group input {
        border: 2px solid #000;
    }
    
    .register-btn {
        border: 2px solid #000;
    }
    
    .btn {
        border: 1px solid currentColor;
    }
}

/* 减少动画模式支持 */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}