Without Width

h1

h2

h3

h4

h5
h6

With width: 5em;

h1

h2

h3

h4

h5
h6

Without Width: margin-left/-right:auto;

h1

h2

h3

h4

h5
h6

With width: 5em; margin-left/-righ:auto;

h1

h2

h3

h4

h5
h6