:root {
    --bg-color: #f5f7fa;
    --card-bg: #ffffff;
    --card-border: #e5e7eb;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --accent-blue: #3b82f6;
    --accent-blue-hover: #2563eb;
    --accent-blue-light: #eff6ff;
    --input-bg: #ffffff;
    --input-border: #d1d5db;
    --input-focus: #3b82f6;
    --error-color: #ef4444;
    --success-color: #10b981;
}

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

body {
    background: var(--bg-color);
    min-height: 100vh;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    position: relative;
}

/* 背景装饰 - 移除深色光晕 */
body::before {
    display: none;
}

/* 浮动光点装饰 - 隐藏 */
.bg-dots {
    display: none;
}

/* 主容器 */
.auth-wrapper {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 440px;
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

/* Logo区 */
.logo-area {
    text-align: center;
    margin-bottom: 24px;
}
.logo-row {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 8px;
}
.logo-img {
    height: 90px;
    width: auto;
    border-radius: 8px;
    flex-shrink: 0;
}
.logo-title {
    font-size: 48px;
    font-weight: 800;
    color: var(--accent-blue);
    letter-spacing: -0.5px;
    line-height: 1;
}
.logo-sub {
    font-size: 0.88rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* 卡片 */
.auth-card {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 32px 32px 28px;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06);
}

/* Tab 切换 */
.tab-bar {
    display: flex;
    background: #f3f4f6;
    border-radius: 12px;
    padding: 4px;
    margin-bottom: 24px;
}
.tab-btn {
    flex: 1;
    padding: 10px 0;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: inherit;
    letter-spacing: 0.5px;
}
.tab-btn.active {
    background: #ffffff;
    color: var(--accent-blue);
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);
}
.tab-btn:hover:not(.active) {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.5);
}

/* 表单区域 */
.form-section {
    display: none;
}
.form-section.active {
    display: block;
    animation: fadeIn 0.22s ease;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(6px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* 表单组 */
.form-group {
    margin-bottom: 20px;
}
.form-label {
    display: block;
    font-size: 0.875rem;
    color: var(--text-primary);
    margin-bottom: 8px;
    font-weight: 500;
}
.form-input-wrap {
    position: relative;
}
.form-input-wrap .icon {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    opacity: 0.4;
    pointer-events: none;
    stroke: var(--text-secondary);
}
.form-input {
    width: 100%;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 10px;
    padding: 12px 14px 12px 42px;
    color: var(--text-primary);
    font-size: 0.95rem;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}
.form-input::placeholder {
    color: var(--text-muted);
}
.form-input:focus {
    border-color: var(--input-focus);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}
/* 密码显示切换 */
.pwd-toggle {
    position: absolute;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
    color: var(--text-muted);
    transition: color 0.15s;
}
.pwd-toggle:hover { color: var(--accent-blue); }
.pwd-toggle svg { width: 18px; height: 18px; display: block; }

/* 忘记密码 */
.form-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
    margin-top: -4px;
}
.remember-label {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    user-select: none;
}
.remember-label input[type="checkbox"] {
    accent-color: var(--accent-blue);
    width: 16px;
    height: 16px;
    cursor: pointer;
}
.forgot-link {
    font-size: 0.875rem;
    color: var(--accent-blue);
    text-decoration: none;
    transition: color 0.15s;
}
.forgot-link:hover { color: var(--accent-blue-hover); }

/* 主按钮 */
.btn-primary {
    width: 100%;
    padding: 14px;
    background: var(--accent-blue);
    border: none;
    border-radius: 10px;
    color: #ffffff;
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    letter-spacing: 0.5px;
    transition: background 0.2s, transform 0.1s, box-shadow 0.2s;
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.25);
}
.btn-primary:hover {
    background: var(--accent-blue-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}
.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.25);
}
.btn-primary.loading {
    pointer-events: none;
    opacity: 0.7;
}
.btn-primary .spinner {
    display: inline-block;
    width: 16px; height: 16px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    vertical-align: middle;
    margin-right: 8px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* 分隔线 */
.divider {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 24px 0;
}
.divider::before, .divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--card-border);
}
.divider span {
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
}

/* 注册协议 */
.agreement {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-align: center;
    margin-top: 16px;
    line-height: 1.7;
}
.agreement a {
    color: var(--accent-blue);
    text-decoration: none;
}
.agreement a:hover { text-decoration: underline; }

/* 消息提示 */
.msg-box {
    padding: 12px 14px;
    border-radius: 8px;
    font-size: 0.875rem;
    margin-bottom: 16px;
    display: none;
    align-items: center;
    gap: 8px;
}
.msg-box.show { display: flex; animation: fadeIn 0.2s ease; }
.msg-box.error {
    background: #fef2f2;
    border: 1px solid #fecaca;
    color: var(--error-color);
}
.msg-box.success {
    background: #ecfdf5;
    border: 1px solid #d1fae5;
    color: var(--success-color);
}

/* 页面底部 */
footer {
    flex-shrink: 0;
    width: 100%;
}

/* 底部链接 */
.bottom-tip {
    text-align: center;
    margin-top: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
}
.switch-link {
    color: var(--accent-blue);
    text-decoration: none;
    font-weight: 600;
    cursor: pointer;
    transition: color 0.15s;
}
.switch-link:hover { color: var(--accent-blue-hover); }

/* 密码强度 */
.pwd-strength {
    margin-top: 8px;
    display: none;
}
.pwd-strength.show { display: block; }
.strength-bar {
    display: flex;
    gap: 4px;
    margin-bottom: 6px;
}
.strength-seg {
    flex: 1;
    height: 4px;
    border-radius: 2px;
    background: #e5e7eb;
    transition: background 0.3s;
}
.strength-seg.weak   { background: #ef4444; }
.strength-seg.fair   { background: #f59e0b; }
.strength-seg.good   { background: #3b82f6; }
.strength-seg.strong { background: #10b981; }
.strength-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* 校验错误提示 */
.field-error {
    font-size: 0.8rem;
    color: var(--error-color);
    margin-top: 6px;
    display: none;
    animation: shake 0.3s ease;
}
.field-error.show { display: block; }
.form-input.invalid {
    border-color: var(--error-color);
    animation: shake 0.3s ease;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

/* 输入框动画 */
.form-input {
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.form-input:focus {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15);
}

/* 按钮点击效果 */
.btn-primary {
    position: relative;
    overflow: hidden;
}

.btn-primary::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn-primary:active::after {
    width: 300px;
    height: 300px;
}

/* 表单切换动画增强 */
.form-section {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.form-section.active {
    opacity: 1;
    transform: translateY(0);
}

/* 标签切换滑动效果 */
.tab-bar {
    position: relative;
}

.tab-btn {
    position: relative;
    z-index: 1;
}

/* Logo 呼吸动画 - 已禁用 */
/* 
.logo-img {
    animation: breathe 3s ease-in-out infinite;
}

@keyframes breathe {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.02); }
}
*/

/* 响应式设计优化 */
@media (max-width: 480px) {
    .auth-wrapper {
        padding: 16px;
        max-width: 100%;
    }
    
    .auth-card {
        padding: 24px 20px;
        border-radius: 12px;
    }
    
    .logo-img {
        height: 70px;
    }
    
    .tab-btn {
        padding: 12px 0;
        font-size: 0.9rem;
    }
    
    .form-group {
        margin-bottom: 16px;
    }
    
    .form-input {
        padding: 14px 14px 14px 42px;
        font-size: 16px; /* 防止iOS缩放 */
    }
    
    .btn-primary {
        padding: 16px;
        font-size: 1rem;
    }
    
    .form-meta {
        flex-direction: column;
        gap: 12px;
        align-items: flex-start;
    }
}

@media (max-width: 360px) {
    .auth-card {
        padding: 20px 16px;
    }
    
    .logo-img {
        height: 60px;
    }
}

/* 平板适配 */
@media (min-width: 481px) and (max-width: 768px) {
    .auth-wrapper {
        max-width: 420px;
    }
}

/* 暗色模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --bg-color: #0f172a;
        --card-bg: #1e293b;
        --card-border: #334155;
        --text-primary: #f1f5f9;
        --text-secondary: #94a3b8;
        --text-muted: #64748b;
        --input-bg: #1e293b;
        --input-border: #475569;
    }
    
    body {
        background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    }
    
    .tab-bar {
        background: #334155;
    }
    
    .tab-btn.active {
        background: #1e293b;
    }
}

/* 减少动画偏好 */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    /* .logo-img 动画已禁用 */
}