\documentclass{beamer}
\usetheme{default}
\beamertemplatenavigationsymbolsempty
\setbeamertemplate{frametitle}[default][center]
\usepackage[skins,theorems]{tcolorbox}
\newtcolorbox{myframe}[2][]{%
boxrule=0.8mm, text width=7.5cm, text height=1.5cm, enhanced,colback=white,colframe=framecolour,coltitle=comcolor,
sharp corners,
fonttitle=\itshape,
attach boxed title to top left={yshift=-0.3\baselineskip-0.4pt,xshift=2mm},
boxed title style={tile,size=minimal,left=0.5mm,right=0.5mm,
colback=white,before upper=\strut},