uBlock/src/css/dyna-rules.css

html {
    height: 100vh;
    overflow: hidden;
    width: 100vw;
    }
body {
    display: flex;
    flex-direction: column;
    height: 100%;
    justify-content: stretch;
    overflow: hidden;
    width: 100%;
    }
.body {
    flex-shrink: 0;
    }
#diff {
    border: 0;
    white-space: nowrap;
}
#diff .tools > * {
    margin-bottom: 1em;
    }
#diff .ruleActions {
    border: 0;
    box-sizing: border-box;
    display: inline-block;
    padding: 0;
    text-align: center;
    vertical-align: top;
    width: 50%;
    white-space: nowrap;
    }
#diff .ruleActions .fieldset-header {
    margin: 0.5em 0;
    }

#ruleFilter {
    align-items: center;
    background-color: var(--surface-2);
    direction: ltr;
    display: flex;
    justify-content: center;
    padding: 0.5em 0;
    }
#ruleFilter #diffCollapse {
    padding: 0 0.5em;
    font-size: 150%;
    }
#ruleFilter #diffCollapse.active {
    transform: scale(1, -1);
    }

.codeMirrorContainer {
    flex-grow: 1;
    }
.codeMirrorContainer .CodeMirror {
    background-color: var(--surface-1);
    }
.CodeMirror-merge, .CodeMirror-merge-pane, .CodeMirror-merge .CodeMirror {
    box-sizing: border-box;
    height: 100%;
    }
body.editing .CodeMirror-merge-copy,
body.editing .CodeMirror-merge-copy-reverse {
    display: none;
    }
body.editing .CodeMirror-merge-editor .CodeMirror {
    background-color: var(--surface-0);
    }
body[dir="rtl"] .CodeMirror-merge-pane-rightmost {
    right: unset;
    left: 0;
}

/* mobile devices */
:root.mobile #diff .tools {
    overflow: auto;
    }