Hi Jain ,

Try

<form string="allocation_form">

<style>

.o_form_view .o_form_statusbar > .o_statusbar_status > .o_arrow_button.btn-primary.disabled[data-value="draft"] {

background: blue;

}

.o_form_view .o_form_statusbar > .o_statusbar_status >

.o_arrow_button.btn-primary.disabled[data-value="draft"]::after {

border-left-color: blue;

}

.o_form_view .o_form_statusbar > .o_statusbar_status > .o_arrow_button.btn-primary.disabled[data-value = "cancel"] {

background: green;

}

.o_form_view .o_form_statusbar > .o_statusbar_status > .o_arrow_button.btn-primary.disabled[data-value =

"cancel"]::after {

border-left-color: green;

}

</style>

<header>

<field name="state" widget="statusbar" statusbar_visible="draft,cancel"/>

</header>

Hope it Helps

Kiran K

Thank you so much Kiran K