/* ========================================
   背景图支持
   ======================================== */

body.has-background {
    position: relative;
}

body.has-background::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;
    z-index: -1;
}

body.has-background .auth-container,
body.has-background .landing-page .hero,
body.has-background .landing-page .feature {
    background: rgba(255, 255, 255, 0.95);
}

/* 原有样式保持不变... */

/* ========================================
   基础样式
   ======================================== */

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

:root {
    --primary-color: #007bff;
    --primary-hover: #0056b3;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #17a2b8;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --border-color: #dee2e6;
    --text-color: #333;
    --text-muted: #6c757d;
    --bg-color: #fff;
    --bg-secondary: #f5f5f5;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --radius: 8px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: 14px;
    line-height: 1.5;
    color: var(--text-color);
    background-color: var(--bg-secondary);
}

a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* ========================================
   按钮样式
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 500;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    gap: 8px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #fff;
}

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-hover);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: #fff;
}

.btn-secondary:hover:not(:disabled) {
    background-color: #5a6268;
}

.btn-success {
    background-color: var(--success-color);
    color: #fff;
}

.btn-danger {
    background-color: var(--danger-color);
    color: #fff;
}

.btn-block {
    display: flex;
    width: 100%;
}

.btn-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    padding: 0;
    font-size: 18px;
    background: transparent;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-icon:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

/* ========================================
   表单样式
   ======================================== */

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px 16px;
    font-size: 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
}

.form-group .hint {
    display: block;
    margin-top: 6px;
    font-size: 12px;
    color: var(--text-muted);
}

.input-with-btn {
    display: flex;
    gap: 10px;
}

.input-with-btn input {
    flex: 1;
}

.input-with-btn .btn {
    white-space: nowrap;
    flex-shrink: 0;
}

/* ========================================
   消息提示
   ======================================== */

.message {
    padding: 12px 16px;
    margin-top: 20px;
    border-radius: var(--radius);
    font-size: 14px;
    display: none;
}

.message.show {
    display: block;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.message.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

/* ========================================
   徽章
   ======================================== */

.badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 18px;
    height: 18px;
    padding: 0 6px;
    font-size: 11px;
    font-weight: 600;
    color: #fff;
    background-color: var(--danger-color);
    border-radius: 9px;
}

/* ========================================
   头像
   ======================================== */

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    background-color: var(--bg-secondary);
}

.avatar-sm {
    width: 32px;
    height: 32px;
}

.avatar-lg {
    width: 60px;
    height: 60px;
}

.avatar-xl {
    width: 80px;
    height: 80px;
}

/* ========================================
   落地页样式
   ======================================== */

.landing-page {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
}

.hero {
    text-align: center;
    margin-bottom: 60px;
    padding: 40px;
    border-radius: var(--radius);
}

.hero h1 {
    font-size: 48px;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 16px;
}

.hero p {
    font-size: 18px;
    color: var(--text-muted);
    margin-bottom: 32px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

.hero-buttons .btn {
    padding: 14px 32px;
    font-size: 16px;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    max-width: 1000px;
    width: 100%;
}

.feature {
    background: var(--bg-color);
    padding: 30px;
    border-radius: var(--radius);
    text-align: center;
    box-shadow: var(--shadow);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature h3 {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-color);
}

.feature p {
    font-size: 14px;
    color: var(--text-muted);
}

/* ========================================
   认证页面样式
   ======================================== */

.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.auth-container {
    width: 100%;
    max-width: 420px;
    background: var(--bg-color);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.auth-container h2 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 24px;
    color: var(--text-color);
}

.login-tabs {
    display: flex;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--border-color);
}

.login-tabs .tab-btn {
    flex: 1;
    padding: 12px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-muted);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
}

.login-tabs .tab-btn.active {
    color: var(--primary-color);
    border-bottom-color: var(--primary-color);
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

.auth-footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

/* QQ登录样式 */
.qq-login-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.qq-login-options .btn small {
    display: block;
    font-size: 11px;
    opacity: 0.8;
    margin-top: 4px;
}

.qq-sub-form {
    margin-top: 20px;
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
}

.code-info {
    text-align: center;
    padding: 20px;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    margin: 16px 0;
}

.verification-code {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: 4px;
    color: var(--primary-color);
    margin: 16px 0;
}

/* ========================================
   加载动画
   ======================================== */

.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px;
    color: var(--text-muted);
}

.loading::before {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    margin-right: 10px;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ========================================
   响应式
   ======================================== */

@media (max-width: 768px) {
    .hero h1 {
        font-size: 32px;
    }

    .hero p {
        font-size: 16px;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .auth-container {
        padding: 24px;
    }
    
    .input-with-btn {
        flex-direction: column;
    }
    
    .input-with-btn .btn {
        width: 100%;
    }
}