body {
    color: #20242a;
    font-family: Arial, sans-serif;
    line-height: 1.4;
    margin: 24px;
}

button,
select {
    font: inherit;
}

section {
    margin-bottom: 24px;
}

.sound-meter {
    background: #e7e9ee;
    border: 1px solid #c7ccd4;
    height: 16px;
    margin: 12px 0;
    max-width: 480px;
    overflow: hidden;
}

.sound-meter__level {
    background: #1769e0;
    height: 100%;
    transition: width 80ms linear;
    width: 0%;
}

#soundWaveform {
    background: #f7f8fa;
    border: 1px solid #c7ccd4;
    display: block;
    max-width: 100%;
}

.feature-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
    border-bottom: 1px solid #c7ccd4;
}
.feature-tabs button {
    padding: 8px 12px;
    border: 0;
    border-bottom: 3px solid transparent;
    background: transparent;
    cursor: pointer;
}
.feature-tabs button[aria-selected="true"] {
    border-bottom-color: #1769e0;
    font-weight: bold;
}
[hidden] { display: none !important; }
#messages, #sentMessages {
    height: 320px;
    overflow-y: auto;
    overflow-wrap: anywhere;
}