Perfect rounded corners in MyBB

[Rana Anas]

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I did follow all above steps now i Cant understand from here what to do please explain me in more easy words

Click on Edit Stylesheet: Advanced Mode on your global.css file and add the follow:

/* Selects the bottom lefthand corner of your tables. */
tr:last-child > .trow1:first-child, tr:last-child > .trow2:first-child,  tbody:last-child tr:last-child > .tcat:first-child {
	-webkit-border-bottom-left-radius: 4px;
	-moz-border-radius-bottomleft: 4px;
	border-bottom-left-radius: 4px;
}

/* Selects the bottom righthand corner of your tables. */
tr:last-child > .trow1:last-child, tr:last-child > .trow2:last-child{
	-webkit-border-bottom-right-radius: 4px;
	-moz-border-radius-bottomright: 4px;
	border-bottom-right-radius: 4px;
}

/* Selects any table with the ID containing 'post' and gets rid of the rounding - this is for the showthread template. */
table[id*="post_"], td.post_buttons, tborder.posthead, tbody[id*="usercpp"] > tr:last-child > td, tbody[id*="modcpforums"] > tr:last-child > td{
	-webkit-border-radius: !important;
	-moz-border-radius: 0!important;
	border-radius: 0!important;
}

/* The custom template ID we added in to get rid of the ugly rounding on the showthread .thead */
table[id="notop"]{
	-webkit-border-bottom-right-radius: 0!important;
	-webkit-border-bottom-left-radius: 0!important;
	-moz-border-radius-bottomright: 0!important;
	-moz-border-radius-bottomleft: 0!important;
	border-bottom-right-radius: 0!important;
	border-bottom-left-radius: 0!important;
}

/* The custom template ID we added in to get rid of the ugly rounding on the showthread .tfoot */
table[id="nobottom"]{
	-webkit-border-top-left-radius: 0!important;
	-webkit-border-top-right-radius: 0!important;
	-moz-border-radius-topleft: 0!important;
	-moz-border-radius-topright: 0!important;
	border-top-left-radius: 0!important;
	border-top-right-radius: 0!important;
}

Scroll down in that box! I've added comments to explain what each segment does.
Edit: Added code to round the .tcat used in the Calendar. Thanks to Ryuuseiken for pointing it out.