:root {
    --color-red: #e12;
    --color-blue: #aef;
    --color-pale: #f3f3f3;
    --color-light: #ddd;
    --color-gray: #999;
    --color-dark: #333;

    --color-text: var(--color-dark);
    --color-background: var(--color-pale);

    --color-selected-color: black;
    --color-selected-background: #60c3;

    --color-head-text: white;
    --color-head-background: #2b3238;

    --color-panel-text: var(--color-pale);
    --color-panel-background: #333b42;

    --header-height: 3rem;
    --aside-width: 240px;
    --input-box-height: 3rem;
}


@custom-media --pc (min-width: 720px);

:root {
    --color-red: #e12;
    --color-blue: #aef;
    --color-pale: #f3f3f3;
    --color-light: #ddd;
    --color-gray: #999;
    --color-dark: #333;

    --color-text: var(--color-dark);
    --color-background: var(--color-pale);

    --color-selected-color: black;
    --color-selected-background: #60c2;

    --color-head-text: white;
    --color-head-background: #2b3238;

    --color-panel-text: var(--color-pale);
    --color-panel-background: #333b42;

    --header-height: 3rem;
    --aside-width: 240px;
    --input-box-height: 3rem;
}


@custom-media --pc (min-width: 720px);

Add some opacity for selection background color
Add some opacity for selection background color
