Grav-Admin-Plugin/themes/grav/scss/template/_editor.scss

// Grav Editor
.grav-editor {
    [data-grav-editor] {
        height: 300px;
    }

    .CodeMirror-scroll {
        margin-right: -36px;
        padding-bottom: 36px;
    }

}

.grav-editor-fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    z-index: 99999;
    padding: 0 !important;
    margin: 0 !important;

    .grav-editor-content, .CodeMirror-wrap, .grav-editor-preview {
        height: 100% !important;
    }

    .grav-editor-toolbar, .grav-editor-toolbar ul li:first-child a, .grav-editor-toolbar-flip ul li:last-child a {
        border-radius: 0;
    }
}

.grav-editor-toolbar {
    @include clearfix;
    border: 1px solid $form-border;
    border-top-right-radius: $form-border-radius;
    border-top-left-radius: $form-border-radius;
    background: lighten($content-bg, 5%);

    ul {
        list-style: none;
        margin: 0;
        padding: 0;

        li {
            &:first-child a {
                border-top-left-radius: 4px;
            }
            display: inline-block;
        }
        .editor-active a {
            background: white;
            cursor: auto;
            border-left: 1px solid $form-border;
            border-right: 1px solid $form-border;
            &:hover {
                background: $white;
            }
        }

        a {
            display: inline-block;
            cursor: pointer;
            color: $content-fg;
            background-color: transparent;
            border-radius: 0;
            padding: 0.4rem 0.8rem;
            margin-top: -1px;
            border: 1px solid transparent;

            &, &:hover, &:active, &:focus {
                outline: 0;
            }

            &:hover, &:focus {
                background: lighten($content-bg, 2%);
                color: darken($content-fg, 10%);
                border-top: 1px solid darken($content-bg, 20%);
                border-bottom: 1px solid darken($content-bg, 20%);
            }
        }
    }


}

.grav-editor-actions {
    &.left {
        float: left;
    }

    &.right {
        float: right;
    }
}

.grav-editor-toolbar-flip {
    float: right;
    ul li:last-child a {
        border-top-right-radius: 4px;
    }
}

.grav-editor-content {

    @include clearfix;
    cursor: text;
    border: 1px solid $form-border;
    border-top: 0;
    border-bottom-right-radius: $form-border-radius;
    border-bottom-left-radius: $form-border-radius;
}

.grav-editor-content {
    .CodeMirror {
        padding: 10px 20px 20px 20px;
        border-bottom-left-radius: $form-border-radius;

    }
}

.grav-editor-preview {
    padding: 20px;
    overflow-y: scroll;
    position: relative;
    background: #fbfbfb;
    border-bottom-right-radius: $form-border-radius;
}

.grav-editor-toolbar {
    p {
        margin-top: 10px;
        margin-bottom: 10px;
        padding-left: 20px;
    }
}

#admin-main {
    .grav-editor-preview {
        font-family: $font-family-default;

        h1, h2, h3, h4, h5, h6 {
            color: darken($content-fg, 10%);
        }
        h1 {
            font-size: 2rem;
            border: 0;
        }
        h2 {
            font-size: 1.6rem;
        }
        h3 {
            font-size: 1.4rem;
        }
        h4 {
            font-size: 1.2rem;
        }
        h5 {
            font-size: 1.1rem
        }
        p, h1 {
            padding: 0;
        }
    }
}

[data-mode=tab] {
    &[data-active-tab=code] .grav-editor-preview, &[data-active-tab=preview] .grav-editor-code {
        display: none;
    }
}

// CodeMirror Theme
.cm-s-paper {

    $paper-fg: darken($content-fg,5%);
    $tag: #349886;

    &.CodeMirror {
        color: $paper-fg;
        font-size: 14px;
        line-height: 1.4;

        pre {
            font-family: "DejaVu Sans Mono", Menlo, Monaco, Consolas, Courier, monospace;
        }
    }

    .cm-link {color: darken($core-accent, 10%);}
    .cm-comment {color: lighten($paper-fg,10%);}
    .cm-header {color: darken($paper-fg,10%);}
    .cm-strong {color: darken($paper-fg,5%);}
    .cm-em {color: darken($paper-fg, 10%);}
    .cm-string {color: $core-accent;}
    .cm-tag {color: $tag}
    .cm-bracket {color: lighten($tag, 10%);}
    .cm-variable {color: darken($paper-fg,10%);}
    .cm-variable-2 {color: lighten($paper-fg,10%);}
    .cm-variable-3 {color: lighten($paper-fg,15%);}
    .cm-hr {color: lighten($paper-fg,40%);font-weight: bold;}

    .cm-keyword {color: $core-accent;}
    .cm-atom {color: $info-bg;}
    .cm-meta {color: $paper-fg;}

    .cm-number {color: #7f8c8d;}
    .cm-def {color: #00f;}
    .cm-variable {color: black;}
    .cm-variable-2 {color: #555;}
    .cm-variable-3 {color: #085;}
    .cm-property {color: black;}
    .cm-operator {color: black;}


    .cm-string-2 {color: #f50;}
    .cm-meta {color: #555;}
    .cm-error {color: #f00;}
    .cm-qualifier {color: #555;}
    .cm-builtin {color: #555;}


    .cm-attribute {color: #7f8c8d;}

    .cm-quote {color: #888;}


    .cm-header-1 {font-size: 140%;}
    .cm-header-2 {font-size: 120%;}
    .cm-header-3 {font-size: 110%;}

    .cm-negative {color: #d44;}
    .cm-positive {color: #292;}
    .cm-header, .cm-strong {font-weight: bold;}
    .cm-em {font-style: italic;}
    .cm-link {text-decoration: underline;}

    .cm-invalidchar {color: #f00;}
}