TechDay-Bruchsal-2026-Seite ergänzt

- public/techday.html: Eventseite im Landingpage-Stil mit Hero,
  Event-Beschreibung, Vortrag (Speaker David Bertram), mITapp-Abschnitt
  mit Platzhaltern, GameJam-Verweis und Event-Infos
- styles.css: Styles für TechDay-Seite (Hero, Talk-Split, Speaker-Karte,
  Screenshot-Platzhalter)
- index.html: Navigations-Verweis "TechDay" in Header, Mobilmenü und
  Footer; GameJam zusätzlich im Footer

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

public/styles.css

@@ -728,6 +728,117 @@ a { color: inherit; text-decoration: none; }
   html { scroll-behavior: auto; }
 }
 
+/* ============================================================
+   TECHDAY-SEITE
+   ============================================================ */
+.td-hero { padding: 88px 0; border-bottom: 1px solid var(--line); }
+.td-hero .eyebrow { margin-bottom: 22px; }
+.td-title {
+  font-size: clamp(34px, 4.6vw, 60px);
+  line-height: 1.06;
+  letter-spacing: -.022em;
+  font-weight: 700;
+  margin-bottom: 22px;
+  max-width: 15em;
+}
+.td-lead {
+  font-size: 17px;
+  color: var(--gray-1);
+  max-width: 40em;
+  margin-bottom: 30px;
+}
+
+.td-split {
+  display: grid;
+  grid-template-columns: 1.45fr 1fr;
+  gap: 56px;
+  align-items: start;
+}
+.td-talk-kicker {
+  font-size: 12px;
+  font-weight: 700;
+  letter-spacing: .14em;
+  text-transform: uppercase;
+  color: var(--gray-2);
+  margin-bottom: 12px;
+}
+.td-talk-title {
+  font-size: clamp(24px, 3vw, 34px);
+  font-weight: 700;
+  letter-spacing: -.02em;
+  line-height: 1.12;
+  margin-bottom: 10px;
+}
+.td-talk-sub {
+  font-size: 16px;
+  color: var(--gray-1);
+  margin-bottom: 26px;
+}
+.td-talk-body p {
+  font-size: 15px;
+  color: var(--gray-1);
+  margin-bottom: 12px;
+}
+
+.speaker-card {
+  border: 1px solid var(--line-strong);
+  background: var(--paper);
+  padding: 28px 26px;
+}
+.speaker-card .sp-label {
+  font-size: 11px;
+  letter-spacing: .14em;
+  text-transform: uppercase;
+  font-weight: 700;
+  color: var(--gray-2);
+  margin-bottom: 16px;
+}
+.speaker-card .sp-name {
+  font-size: 20px;
+  font-weight: 700;
+  letter-spacing: -.01em;
+}
+.speaker-card .sp-role {
+  font-size: 14px;
+  color: var(--gray-1);
+  margin-bottom: 14px;
+}
+.speaker-card .sp-bio {
+  font-size: 14px;
+  color: var(--gray-1);
+}
+
+/* Platzhalter für mITapp-Screenshots (folgen vom Betreiber) */
+.placeholder-grid {
+  display: grid;
+  grid-template-columns: repeat(3, 1fr);
+  gap: 16px;
+  margin-top: 8px;
+}
+.placeholder-img {
+  border: 1.5px dashed var(--line-strong);
+  background: var(--paper-2);
+  aspect-ratio: 4 / 3;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  text-align: center;
+  padding: 16px;
+  font-size: 11px;
+  letter-spacing: .12em;
+  text-transform: uppercase;
+  font-weight: 700;
+  color: var(--gray-2);
+}
+
+@media (max-width: 820px) {
+  .td-split { grid-template-columns: 1fr; gap: 36px; }
+  .placeholder-grid { grid-template-columns: 1fr 1fr; }
+}
+@media (max-width: 560px) {
+  .placeholder-grid { grid-template-columns: 1fr; }
+}
+
 /* ============================================================
    RECHTLICHE SEITEN (Impressum / Datenschutz)
    ============================================================ */