* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}
body {
    background-color: #f5f5f5;
    color: #333;
}
header {
    background: white;
    padding: 12px 16px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 10;
}
nav {
    display: flex;
    margin-top: 12px;
    gap: 8px;
    overflow-x: auto;
    padding-bottom: 4px;
}
.nav-btn {
    padding: 8px 16px;
    background: #f0f0f0;
    border: none;
    border-radius: 20px;
    font-size: 14px;
    white-space: nowrap;
    cursor: pointer;
    transition: all 0.2s;
}
.nav-btn.active {
    background: #009688;
    color: white;
}
#content {
    padding: 16px;
}
.loader {
    text-align: center;
    padding: 40px;
    color: #999;
}