custom-marker.html

<dom-module id="custom-marker">
    <style>
        :host {
            position: absolute;
            transform: translate(-50%, -50%);
            cursor: default;
            transition: box-shadow .3s ease;
        }

        :host(:hover), :host(:active) {
            z-index: 999999999;
        }

        :host([position="top"]) {
            transform: translate(-50%, -100%);
        }

        :host([position="center"]) {
            transform: translate(-50%, -50%);
        }

        :host([position="bottom"]) {
            transform: translate(-50%, 0);
        }

        :host([position="left"]) {
            transform: translate(-100%, -50%);
        }

        :host([position="right"]) {
            transform: translate(0, -50%);
        }

    </style>
    <template>
        <content></content>
    </template>
</dom-module>
<script>
	(function () {

		Polymer({

			is: 'custom-marker',

			properties: {
				position: {
					type: String,
					reflectToAttribute: true
				}
			},

			listeners: {
				'tap': '_onTap'
			},

			_onTap: function (event) { }

		});

	})();
</script>