feat(user-center): redesign sidebar and wallet tips

assets/css/frontend/enhancements/components/base.css

@@ -197,3 +197,64 @@
     background: var(--surface-3, #ECEEF1);
 }
 
+
+
+.reward-modal__content > p {
+  margin: -4px 0 18px;
+}
+
+.reward-amounts {
+  display: grid;
+  grid-template-columns: repeat(3, minmax(0, 1fr));
+  gap: 10px;
+  margin: 18px 0;
+}
+
+.reward-amount {
+  min-height: 42px;
+  border: 1px solid var(--color-line-soft, rgba(15, 23, 42, 0.1));
+  border-radius: 10px;
+  background: var(--surface-2);
+  color: var(--color-ink-2);
+  cursor: pointer;
+  font-weight: 700;
+}
+
+.reward-amount.is-active {
+  border-color: var(--color-primary);
+  background: var(--color-primary-soft);
+  color: var(--color-primary);
+}
+
+.reward-custom {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 12px;
+  margin-bottom: 16px;
+  color: var(--color-ink-3);
+  font-size: 13px;
+}
+
+.reward-custom input {
+  width: 140px;
+  min-height: 40px;
+  border: 1px solid var(--color-line-soft, rgba(15, 23, 42, 0.1));
+  border-radius: 9px;
+  background: var(--surface-1);
+  color: var(--color-ink);
+  padding: 0 12px;
+}
+
+.reward-modal__submit {
+  width: 100%;
+  min-height: 42px;
+}
+
+.reward-modal__message {
+  min-height: 20px;
+  margin-top: 10px;
+  color: var(--color-primary);
+  font-size: 12px;
+  text-align: center;
+}