Sample file for theme developers include the CSS classes for most frontend Paid Memberships Pro elements.

blank_frontend.css

/*---------------------------------------
	Buttons
---------------------------------------*/
.pmpro_btn {}
.pmpro_content_message a {}
.pmpro_btn.disabled {}
.pmpro_btn.pmpro_btn-cancel {}
.pmpro_btn.pmpro_btn-submit-checkout {}
input[type="button"]#discount_code_button {}
input[type="button"]#other_discount_code_button {}
button[type="button"]#other_discount_code_toggle {}

/*---------------------------------------
	Forms
---------------------------------------*/

/* -- Checkout, Billing Information, etc. --*/
form.pmpro_form .pmpro_checkout-fields div {}
form.pmpro_form label {}
form.pmpro_form label.pmpro_label-inline {}
form.pmpro_form label.pmpro_clickable {}
form.pmpro_form .pmpro_asterisk abbr {}
form.pmpro_form .pmpro_captcha div {}
form.pmpro_form .pmpro_submit {}
form.pmpro_form #pmpro_processing_message {}
form.pmpro_form input[type=text] {}
form.pmpro_form input[type=password] {}
form.pmpro_form input[type=email] {}
form.pmpro_form input[type=number] {}
form.pmpro_form textarea {}
form.pmpro_form select {}

/*---------------------------------------
	Log In and Password Reset Pages
---------------------------------------*/
.pmpro_login_wrap, .pmpro_lost_password_wrap, .pmpro_reset_password_wrap {}
#loginform p {}
#loginform label {}
#loginform input[type=text] {}
#loginform input[type=password] {}

/* -- Reset Password (not logged in) --*/
.pmpro_reset_password_wrap form.pmpro_form {}

/*--------------------------------------------------
	Messages - Success, Error, Alert
----------------------------------------------------*/
.pmpro_message {  }
.pmpro_message p:last-child {  }
.pmpro_success {  }
.pmpro_error
.pmpro_alert {  }
.pmpro_message a {  }
.pmpro_success a {  }
.pmpro_error a {  }
.pmpro_alert a {  }

/*---------------------------------------
	Display Price Parts
---------------------------------------*/
.pmpro_price_part_span {
	display: block;
}
.pmpro_price_part-total {
	border-top: 1px solid #CCC;
	margin-top: 5px;
	padding-top: 5px;
}
.pmpro_price_part_label:after {
	content: ": ";
}
.pmpro_price_part_sub {
	font-size: 75%;
}
span.pmpro_price_part_sub:before {
	content: "\2022";
	padding-right: 5px;
}

/*---------------------------------------
	Membership Checkout
---------------------------------------*/
#pmpro_form .pmpro_checkout h2 {}
.pmpro_checkout h2 span.pmpro_checkout-h2-name {}
.pmpro_checkout h2 span.pmpro_checkout-h2-msg {}
#pmpro_license {}

/* Stripe gateway Membership Checkout specific styles. */
.pmpro_checkout_gateway-stripe form.pmpro_form #pmpro_payment_information_fields .pmpro_checkout-field-payment-request-button {}
.pmpro_checkout_gateway-stripe form.pmpro_form #pmpro_payment_information_fields .pmpro_checkout-field-payment-request-button h4 {}

.pmpro_checkout_gateway-stripe form.pmpro_form #pmpro_payment_information_fields .pmpro_checkout-fields, .pmpro_billing_gateway-stripe form.pmpro_form #pmpro_payment_information_fields .pmpro_checkout-fields { }

/*---------------------------------------
	Membership Invoice
---------------------------------------*/
.pmpro_invoice_details {}
.pmpro_invoice_details .pmpro_invoice-billing-address, .pmpro_invoice_details .pmpro_invoice-payment-method, .pmpro_invoice_details .pmpro_invoice-total {}
.pmpro_invoice-field-billing_name, .pmpro_invoice-field-billing_street, .pmpro_invoice-field-billing_country, .pmpro_invoice-field-billing_phone {}

/*---------------------------------------
	Membership Account
---------------------------------------*/
#pmpro_account .pmpro_box {}
#pmpro_account .pmpro_box h2 {}
#pmpro_account #pmpro_account-membership { }
#pmpro_account #pmpro_account-profile { }
#pmpro_account #pmpro_account-billing { }
#pmpro_account #pmpro_account-invoices { }
#pmpro_account #pmpro_account-links { }
.pmpro_actionlinks {}
li.pmpro_more {}

/*---------------------------------------
	Membership Billing Page
---------------------------------------*/
.pmpro_billing_wrap {}

/*---------------------------------------
	Member Profile Edit Page
---------------------------------------*/
.pmpro_member_profile_edit_wrap, .pmpro_change_password_wrap {}
form.pmpro_form .pmpro_change_password-fields {}

/*---------------------------------------
	Membership Levels
---------------------------------------*/
#pmpro_levels_table {}
#pmpro_levels_table td:nth-child(1) {}
#pmpro_levels_table .pmpro_btn {}

/*---------------------------------------
	Misc
---------------------------------------*/
.pmpro_actions_nav {}
.pmpro_actions_nav-left {}
.pmpro_actions_nav-right {}
.pmpro-levels .pmpro_actions_nav {}
.pmpro_a-right {}
.pmpro_a-print {}
.pmpro_red {}
.pmpro_grey {}
.clear {}
.pmpro_small {}