The dasha tab leads with a now card and a duration bar, and keeps sub-periods inside the current details element. A zero-year Chara row stays grey, shows 0 年, and cannot expand. The tropical wheel uses a 520 view box, element bands, separated planet labels, and aspect lines that stay visible while a selected body is highlighted.
A zero-year Chara period is shown as 0 years instead of failing the whole chart. Switching ephemeris dates drops the previous day immediately and can be retried. Missing birth data links to chart settings.
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