.history-action { margin: 1.1rem 0; }
.history-action a { display: inline-block; color: #075985; font-weight: 600; text-decoration: underline; text-underline-offset: .25em; }
.history-event-date { border-left: 3px solid #b45309; padding-left: 1rem; margin: 0 0 2rem; font-weight: 600; color: #92400e; }
.platform-timeline { margin: 2.5rem 0 3.5rem; scroll-margin-top: 6rem; }
.platform-timeline h2 { font-size: clamp(1.75rem, 3vw, 2.35rem); }
.platform-timeline__intro { max-width: 48rem; margin: 1rem 0 2rem; }
.platform-timeline__list { list-style: none; margin: 0; padding: 0 0 0 1.25rem; border-left: 2px solid #0e7490; }
.platform-timeline__item { position: relative; padding: 0 0 1.4rem; }
.platform-timeline__item::before { content: ''; position: absolute; top: 1.8rem; left: -1.65rem; width: .7rem; height: .7rem; background: #b45309; border: 2px solid #fff; border-radius: 50%; box-shadow: 0 0 0 1px #b45309; }
.platform-timeline__card { display: grid; grid-template-columns: 9.5rem minmax(0,1fr); gap: 1.5rem; padding: 1.5rem; border: 1px solid #cbd5e1; border-radius: 8px; color: #1e293b; background: linear-gradient(115deg,#f0f9ff,#fff 60%); transition: border-color 160ms ease, box-shadow 160ms ease; }
.platform-timeline__card:hover { color: #1e293b; border-color: #0e7490; box-shadow: 0 4px 15px rgba(15,23,42,.08); }
.platform-timeline__card:focus-visible, .history-action a:focus-visible { outline: 3px solid #b45309; outline-offset: 4px; }
.platform-timeline__date { color: #075985; font-weight: 600; font-size: 1.05rem; }
.platform-timeline__copy { display: block; min-width: 0; }
.platform-timeline__copy h3 { margin: 0 0 .7rem; font-size: 1.45rem; color: #0f172a; }
.platform-timeline__summary { display: block; line-height: 1.7; }
.platform-timeline__read { display: block; color: #075985; margin-top: .8rem; font-size: .95rem; font-weight: 600; }
#platform-histories { scroll-margin-top: 6rem; }
@media (max-width: 640px) {
    .platform-timeline { margin-top: 1.8rem; }
    .platform-timeline__list { padding-left: 1rem; }
    .platform-timeline__item::before { left: -1.4rem; }
    .platform-timeline__card { grid-template-columns: minmax(0,1fr); gap: .65rem; padding: 1.1rem; }
    .platform-timeline__copy h3 { font-size: 1.35rem; }
}
@media (prefers-reduced-motion: reduce) {
    .platform-timeline__card { transition: none; }
}