feat(exam-prep F10): план по дате экзамена — виджет на дашборде + модалка + GET/PUT/DELETE /plan

frontend/css/exam-prep.css

@@ -830,6 +830,77 @@
   font-size: .72rem; color: var(--text-3);
 }
 
+/* ═══════════════════════════════════════════════════════════════
+   Plan widget (`dh-plan-*`) — used by dashboard (F10)
+   ═══════════════════════════════════════════════════════════════ */
+
+.dh-plan-head {
+  display: flex; align-items: center; justify-content: space-between;
+  margin-bottom: 14px;
+}
+.dh-plan-head h3 { margin-bottom: 0; }
+.dh-plan-edit {
+  width: 32px; height: 32px;
+  border: 1.5px solid var(--border-h);
+  border-radius: 8px;
+  background: var(--surface);
+  color: var(--text-2);
+  cursor: pointer;
+  display: flex; align-items: center; justify-content: center;
+  transition: all .15s;
+}
+.dh-plan-edit:hover { border-color: var(--violet); color: var(--violet); }
+.dh-plan-edit svg { width: 14px; height: 14px; stroke-width: 2; }
+
+.dh-plan-grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
+  gap: 12px;
+}
+.dh-plan-stat {
+  background: rgba(155,93,229,.05);
+  border-radius: 10px;
+  padding: 14px 16px;
+}
+
+.dh-plan-expired {
+  margin-top: 12px; padding: 10px 14px;
+  background: rgba(248,150,30,.10); color: #B45309;
+  border-left: 3px solid #F8961E;
+  border-radius: 6px;
+  font-size: .82rem;
+}
+
+/* Modal form */
+.dh-plan-form {
+  display: flex; flex-direction: column; gap: 14px;
+}
+.dh-plan-field label {
+  display: block; font-size: .78rem; font-weight: 700; color: var(--text-2);
+  text-transform: uppercase; letter-spacing: .04em; margin-bottom: 6px;
+}
+.dh-plan-input {
+  width: 100%;
+  padding: 9px 12px;
+  border: 1.5px solid var(--border-h);
+  border-radius: 9px;
+  background: var(--surface); color: var(--text);
+  font-family: 'Manrope', sans-serif; font-size: .92rem;
+}
+.dh-plan-input:focus { outline: none; border-color: var(--violet); }
+.dh-plan-hint { font-size: .72rem; color: var(--text-3); margin-top: 4px; }
+
+.dh-plan-derived-card {
+  display: flex; flex-direction: column; gap: 5px;
+  padding: 10px 12px;
+  background: rgba(6,214,160,.06);
+  border-left: 3px solid #06D6A0;
+  border-radius: 6px;
+  font-size: .85rem;
+  color: var(--text-2);
+}
+.dh-plan-derived-card b { color: var(--text); }
+
 /* ── Mobile tweaks ─────────────────────────────────────────────── */
 @media (max-width: 640px) {
   .ep-wrap   { padding: 20px 16px 60px; }