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

:root {
    --bg-gradient-start: #667eea;
    --bg-gradient-end: #764ba2;
    --card-bg: rgba(255, 255, 255, 0.95);
    --text-primary: #333;
    --text-secondary: #666;
    --text-muted: #999;
    --accent-color: #667eea;
    --border-color: #eee;
    --input-bg: white;
    --input-border: #eee;
    --flash-success-bg: #d4edda;
    --flash-success-text: #155724;
    --flash-error-bg: #f8d7da;
    --flash-error-text: #721c24;
}

[data-theme="dark"] {
    --bg-gradient-start: #1a1a2e;
    --bg-gradient-end: #16213e;
    --card-bg: rgba(30, 30, 46, 0.95);
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --text-muted: #808080;
    --accent-color: #a78bfa;
    --border-color: #3a3a5a;
    --input-bg: #2a2a3a;
    --input-border: #4a4a6a;
    --flash-success-bg: #1a3a2a;
    --flash-success-text: #6ee7b7;
    --flash-error-bg: #3a1a1a;
    --flash-error-text: #f87171;
}

body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    transition: background 0.3s ease;
}

.container {
    text-align: center;
    padding: 60px 40px;
    background: var(--card-bg);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    max-width: 600px;
    width: 90%;
    animation: fadeIn 0.6s ease-out;
    position: relative;
    transition: background 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.avatar {
    width: 120px;
    height: 120px;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    border-radius: 50%;
    margin: 0 auto 30px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 60px;
    color: white;
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
    transition: all 0.3s ease;
}

h1 {
    font-size: 42px;
    color: var(--text-primary);
    margin-bottom: 15px;
    font-weight: 700;
    transition: color 0.3s ease;
}

.welcome {
    font-size: 24px;
    color: var(--accent-color);
    margin-bottom: 25px;
    font-weight: 500;
    transition: color 0.3s ease;
}

.message {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 30px;
    transition: color 0.3s ease;
}

.auth-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 20px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 25px;
    text-decoration: none;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(102, 126, 234, 0.5);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--accent-color);
    border: 2px solid var(--accent-color);
}

.btn-secondary:hover {
    background: var(--accent-color);
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a5a 100%);
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(238, 90, 90, 0.5);
}

.btn-full {
    width: 100%;
}

.footer {
    font-size: 14px;
    color: var(--text-muted);
    padding-top: 20px;
    border-top: 1px solid var(--border-color);
    margin-top: 20px;
    transition: all 0.3s ease;
}

.footer span {
    color: var(--accent-color);
    font-weight: 600;
}

.sparkle {
    animation: sparkle 2s infinite;
}

@keyframes sparkle {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* 快捷导航栏 */
.quick-nav {
    position: fixed;
    top: 15px;
    right: 80px;
    display: flex;
    gap: 10px;
    z-index: 99;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    background: rgba(255, 255, 255, 0.9);
    border: none;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: #333;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    white-space: nowrap;
}

[data-theme="dark"] .nav-btn {
    background: rgba(40, 40, 60, 0.9);
    color: #e0e0e0;
}

.nav-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .nav-btn:hover {
    background: rgba(60, 60, 80, 0.95);
}

/* 移动端导航 */
@media (max-width: 600px) {
    .quick-nav {
        position: absolute;
        top: auto;
        bottom: -60px;
        right: 50%;
        transform: translateX(50%);
        background: rgba(255, 255, 255, 0.95);
        padding: 10px 15px;
        border-radius: 25px;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    }
    
    [data-theme="dark"] .quick-nav {
        background: rgba(40, 40, 60, 0.95);
    }
    
    .nav-btn {
        padding: 6px 10px;
        font-size: 12px;
    }
}

/* 快捷导航栏 */
.quick-nav {
    position: fixed;
    top: 15px;
    right: 80px;
    display: flex;
    gap: 10px;
    z-index: 99;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    background: rgba(255, 255, 255, 0.9);
    border: none;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 500;
    color: #333;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    white-space: nowrap;
}

[data-theme="dark"] .nav-btn {
    background: rgba(40, 40, 60, 0.9);
    color: #e0e0e0;
}

.nav-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .nav-btn:hover {
    background: rgba(60, 60, 80, 0.95);
}

/* 移动端导航 */
@media (max-width: 600px) {
    .quick-nav {
        position: absolute;
        top: auto;
        bottom: -60px;
        right: 50%;
        transform: translateX(50%);
        background: rgba(255, 255, 255, 0.95);
        padding: 10px 15px;
        border-radius: 25px;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    }
    
    [data-theme="dark"] .quick-nav {
        background: rgba(40, 40, 60, 0.95);
    }
    
    .nav-btn {
        padding: 6px 10px;
        font-size: 12px;
    }
}

/* 主题切换按钮 */
.theme-toggle {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    border: none;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    color: white;
    font-size: 24px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    z-index: 100;
    /* 移动端触摸优化 */
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
    -webkit-touch-callout: none;
    user-select: none;
}

.theme-toggle:hover {
    transform: rotate(20deg) scale(1.1);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

.theme-toggle:active {
    transform: scale(0.95);
}

/* 表单样式 */
.auth-container {
    max-width: 400px;
}

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

.form-group input {
    width: 100%;
    padding: 15px 20px;
    border: 2px solid var(--input-border);
    border-radius: 25px;
    font-size: 16px;
    transition: all 0.3s ease;
    outline: none;
    background: var(--input-bg);
    color: var(--text-primary);
}

.form-group input:focus {
    border-color: var(--accent-color);
}

.form-group input::placeholder {
    color: var(--text-muted);
}

.auth-link {
    margin-top: 20px;
    color: var(--text-secondary);
    font-size: 14px;
}

.auth-link a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 600;
}

.auth-link a:hover {
    text-decoration: underline;
}

/* 消息提示 */
.flash-success {
    background: var(--flash-success-bg);
    color: var(--flash-success-text);
    padding: 12px 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    border: 1px solid transparent;
}

.flash-error {
    background: var(--flash-error-bg);
    color: var(--flash-error-text);
    padding: 12px 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    border: 1px solid transparent;
}

.flash-messages {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}

/* 响应式 */
@media (max-width: 480px) {
    .container {
        padding: 40px 25px;
    }
    
    h1 {
        font-size: 32px;
    }
    
    .welcome {
        font-size: 20px;
    }
    
    .auth-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .theme-toggle {
        top: 10px;
        right: 10px;
        width: 40px;
        height: 40px;
        font-size: 20px;
    }
}