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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: #f5f5f5;
    color: #333;
    padding-bottom: 60px;
}

.container {
    max-width: 480px;
    margin: 0 auto;
    background: #fff;
    min-height: 100vh;
}

.header {
    background: #007AFF;
    color: #fff;
    padding: 15px;
    text-align: center;
    font-size: 18px;
    font-weight: 500;
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-bar {
    position: fixed;
    bottom: 15px;
    left: 50%;
    transform: translateX(-50%);
    width: calc(100% - 40px);
    max-width: 400px;
    background: #fff;
    border-top: none;
    display: flex;
    justify-content: space-around;
    padding: 6px 0 8px 0;
    z-index: 100;
    box-shadow: 0 4px 24px rgba(0, 0, 0, 0.15);
    border-radius: 24px;
}

.nav-item {
    flex: 1;
    text-align: center;
    color: #999;
    text-decoration: none;
    font-size: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 4px 6px;
    border-radius: 12px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
}

.nav-item.active {
    color: #007AFF;
    background: rgba(0, 122, 255, 0.08);
}

.nav-item.active::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 24px;
    height: 2px;
    background: #007AFF;
    border-radius: 0 0 6px 6px;
}

.nav-icon {
    font-size: 18px;
    display: block;
    margin-bottom: 1px;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-item.active .nav-icon {
    transform: scale(1.05);
}

.btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: #007AFF;
    color: #fff;
    border: none;
    border-radius: 16px;
    font-size: 16px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(0, 122, 255, 0.25);
}

.btn:active {
    opacity: 0.8;
}

.btn-secondary {
    background: #f5f5f5;
    color: #333;
}

.form-group {
    margin-bottom: 15px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    color: #666;
    font-size: 14px;
}

.form-input {
    width: 100%;
    padding: 14px 16px;
    border: 1px solid #e5e5e5;
    border-radius: 16px;
    font-size: 14px;
}

.form-input:focus {
    outline: none;
    border-color: #007AFF;
}

.loading {
    text-align: center;
    padding: 20px;
    color: #999;
}

.empty {
    text-align: center;
    padding: 40px 20px;
    color: #999;
}

.toast {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.8);
    background: rgba(0, 0, 0, 0.85);
    color: #fff;
    padding: 14px 28px;
    border-radius: 10px;
    z-index: 9999;
    font-size: 15px;
    max-width: 80%;
    text-align: center;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.toast.show {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
    pointer-events: auto;
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 输入框焦点动画 */
input:focus,
textarea:focus,
select:focus {
    transition: border-color 0.3s, box-shadow 0.3s;
}

/* 按钮点击反馈 */
button,
.btn {
    transition: all 0.2s;
    user-select: none;
}

button:active,
.btn:active {
    transform: scale(0.98);
}

/* 链接样式 */
a {
    transition: color 0.2s;
}

/* 禁用状态 */
button:disabled,
.btn:disabled,
input:disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

/* 加载动画 */
@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 淡入动画 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 响应式设计 */
@media (max-width: 480px) {
    .container {
        max-width: 100%;
    }
}