A blow-molded container comprising: a finish defining an opening at a first end of the container that provides access to an internal volume defined by the container ; and a base portion at a second end of the container opposite to the first end , the base portion including: an external standing surface of the container at an outer diameter of the base portion ; a central push-up portion at a center of the base portion , a longitudinal axis of the container extending through the central push-up portion ; an upstanding wall extending from the external standing surface towards the first end of the container and angled inward away from a sidewall of the container and towards the central push-up portion ; a diaphragm extending between the upstanding wall and the central push-up portion ; and a hinge where the diaphragm mates with the upstanding wall ; wherein: the diaphragm is configured for being drawn from an as-blown first configuration towards the first end of the container to a second configuration, in response to an internal vacuum within the container caused by hot-filling the container ; and the diaphragm is configured for moving from the second configuration to an activated third configuration in response to an external actuation force applied to the diaphragm when being in the second configuration, the diaphragm being closer to the first end of the container in the activated third configuration as compared to the second configuration; characterized in that at least a portion of the upstanding wall is arranged movably towards the sidewall and subsequently away from the sidewall as the base portion moves from the second configuration to the third configuration. a finish defining an opening at a first end of the container that provides access to an internal volume defined by the container ; and a base portion at a second end of the container opposite to the first end , the base portion including: an external standing surface of the container at an outer diameter of the base portion ; a central push-up portion at a center of the base portion , a longitudinal axis of the container extending through the central push-up portion ; an upstanding wall extending from the external standing surface towards the first end of the container and angled inward away from a sidewall of the container and towards the central push-up portion ; a diaphragm extending between the upstanding wall and the central push-up portion ; and a hinge where the diaphragm mates with the upstanding wall ; an external standing surface of the container at an outer diameter of the base portion ; a central push-up portion at a center of the base portion , a longitudinal axis of the container extending through the central push-up portion ; an upstanding wall extending from the external standing surface towards the first end of the container and angled inward away from a sidewall of the container and towards the central push-up portion ; a diaphragm extending between the upstanding wall and the central push-up portion ; and a hinge where the diaphragm mates with the upstanding wall ; wherein: the diaphragm is configured for being drawn from an as-blown first configuration towards the first end of the container to a second configuration, in response to an internal vacuum within the container caused by hot-filling the container ; and the diaphragm is configured for moving from the second configuration to an activated third configuration in response to an external actuation force applied to the diaphragm when being in the second configuration, the diaphragm being closer to the first end of the container in the activated third configuration as compared to the second configuration; characterized in that at least a portion of the upstanding wall is arranged movably towards the sidewall and subsequently away from the sidewall as the base portion moves from the second configuration to the third configuration. <EOS>