Initial commit: TimeClock v3 - Node.js/Vue.js Zeiterfassung

Features:
- Backend: Node.js/Express mit MySQL/MariaDB
- Frontend: Vue.js 3 mit Composition API
- UTC-Zeithandling für korrekte Zeiterfassung
- Timewish-basierte Überstundenberechnung
- Wochenübersicht mit Urlaubs-/Krankheits-/Feiertagshandling
- Bereinigtes Arbeitsende (Generell/Woche)
- Überstunden-Offset für historische Daten
- Fixed Layout mit scrollbarem Content
- Kompakte UI mit grünem Theme

frontend/src/assets/main.css

@@ -0,0 +1,158 @@
+* {
+  box-sizing: border-box;
+}
+
+body {
+  margin: 0;
+  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
+  -webkit-font-smoothing: antialiased;
+  -moz-osx-font-smoothing: grayscale;
+  background-color: #ffffff;
+  color: #000000;
+}
+
+#app {
+  min-height: 100vh;
+  display: flex;
+  flex-direction: column;
+}
+
+h1, h2, h3, h4, h5, h6 {
+  margin-top: 0;
+}
+
+button {
+  cursor: pointer;
+  font-family: inherit;
+}
+
+.container {
+  max-width: 100%;
+  margin: 0 auto;
+  padding: 0 3rem;
+}
+
+/* Utility Classes */
+.card {
+  background: #fafafa;
+  border: 1px solid #e0e0e0;
+  padding: 1.5rem;
+  margin-bottom: 1.5rem;
+  border-radius: 6px;
+  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.04);
+  transition: box-shadow 0.2s, border-color 0.2s;
+}
+
+.card:hover {
+  border-color: #ccc;
+  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.08);
+}
+
+.btn {
+  padding: 0.5rem 1rem;
+  border: 1px solid #ccc;
+  border-radius: 4px;
+  font-weight: normal;
+  font-size: 0.95rem;
+  cursor: pointer;
+  background-color: #f5f5f5;
+  color: #333;
+  transition: background-color 0.2s;
+}
+
+.btn:hover {
+  background-color: #e5e5e5;
+}
+
+.btn-primary {
+  background-color: #5bc0de;
+  border-color: #46b8da;
+  color: white;
+}
+
+.btn-primary:hover {
+  background-color: #31b0d5;
+  border-color: #269abc;
+}
+
+.btn-success {
+  background-color: #5cb85c;
+  border-color: #4cae4c;
+  color: white;
+}
+
+.btn-success:hover {
+  background-color: #449d44;
+  border-color: #398439;
+}
+
+.btn-danger {
+  background-color: #d9534f;
+  border-color: #d43f3a;
+  color: white;
+}
+
+.btn-danger:hover {
+  background-color: #c9302c;
+  border-color: #ac2925;
+}
+
+.btn-secondary {
+  background-color: #6c757d;
+  border-color: #6c757d;
+  color: white;
+}
+
+.btn-secondary:hover {
+  background-color: #5a6268;
+}
+
+.input {
+  width: 100%;
+  padding: 8px 12px;
+  border: 1px solid #ddd;
+  border-radius: 4px;
+  font-size: 14px;
+  transition: border-color 0.2s, box-shadow 0.2s;
+}
+
+.input:focus {
+  outline: none;
+  border-color: #5bc0de;
+  box-shadow: 0 0 0 3px rgba(91, 192, 222, 0.1);
+}
+
+.form-group {
+  margin-bottom: 1.25rem;
+}
+
+.form-group label {
+  display: block;
+  margin-bottom: 0.5rem;
+  font-weight: 500;
+  color: #333;
+}
+
+.grid {
+  display: grid;
+  gap: 1.5rem;
+}
+
+.grid-2 {
+  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
+}
+
+.text-center {
+  text-align: center;
+}
+
+.mt-1 { margin-top: 0.5rem; }
+.mt-2 { margin-top: 1rem; }
+.mt-3 { margin-top: 1.5rem; }
+.mt-4 { margin-top: 2rem; }
+
+.mb-1 { margin-bottom: 0.5rem; }
+.mb-2 { margin-bottom: 1rem; }
+.mb-3 { margin-bottom: 1.5rem; }
+.mb-4 { margin-bottom: 2rem; }
+