feat: BottomNav 모바일 하단 네비게이션 컴포넌트

src/components/BottomNav.css

@@ -0,0 +1,167 @@
+/* BottomNav — mobile bottom navigation */
+
+.bottom-nav {
+  display: none;
+  position: fixed;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  height: var(--bottom-nav-h);
+  padding-bottom: var(--safe-area-bottom);
+  background: var(--bg-secondary);
+  border-top: 1px solid var(--border-line);
+  backdrop-filter: blur(20px);
+  -webkit-backdrop-filter: blur(20px);
+  z-index: 300;
+  align-items: stretch;
+  justify-content: space-around;
+}
+
+@media (max-width: 768px) {
+  .bottom-nav {
+    display: flex;
+  }
+}
+
+/* Primary nav items */
+.bottom-nav__item {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  flex: 1;
+  min-width: 48px;
+  min-height: 48px;
+  gap: 3px;
+  color: var(--text-dim);
+  text-decoration: none;
+  font-family: var(--font-body);
+  font-size: 10px;
+  font-weight: 500;
+  letter-spacing: 0.02em;
+  transition: color 0.18s var(--ease-out);
+  -webkit-tap-highlight-color: transparent;
+  outline: none;
+  border: none;
+  background: none;
+  cursor: pointer;
+  padding: 4px 2px;
+}
+
+.bottom-nav__item:hover,
+.bottom-nav__item.is-active,
+.bottom-nav__item--active {
+  color: var(--neon-cyan);
+}
+
+.bottom-nav__item:hover .bottom-nav__icon,
+.bottom-nav__item.is-active .bottom-nav__icon,
+.bottom-nav__item--active .bottom-nav__icon {
+  filter: drop-shadow(0 0 6px var(--neon-cyan-dim));
+}
+
+/* Icon wrapper */
+.bottom-nav__icon {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  width: 22px;
+  height: 22px;
+  flex-shrink: 0;
+  transition: filter 0.18s var(--ease-out);
+}
+
+.bottom-nav__icon svg,
+.bottom-nav__icon > * {
+  width: 22px;
+  height: 22px;
+}
+
+/* Label */
+.bottom-nav__label {
+  line-height: 1;
+  white-space: nowrap;
+}
+
+/* ---- More overlay backdrop ---- */
+.bottom-nav__more-overlay {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.55);
+  backdrop-filter: blur(4px);
+  -webkit-backdrop-filter: blur(4px);
+  z-index: 298;
+  opacity: 0;
+  pointer-events: none;
+  transition: opacity 0.22s var(--ease-out);
+}
+
+.bottom-nav__more-overlay.is-open {
+  opacity: 1;
+  pointer-events: auto;
+}
+
+/* ---- More panel ---- */
+.bottom-nav__more-panel {
+  position: fixed;
+  bottom: calc(var(--bottom-nav-h) + var(--safe-area-bottom));
+  left: 0;
+  right: 0;
+  z-index: 299;
+  padding: 16px 12px 12px;
+  background: var(--surface-raised);
+  border-top: 1px solid var(--border-line);
+  border-radius: var(--radius-lg) var(--radius-lg) 0 0;
+  display: grid;
+  grid-template-columns: repeat(4, 1fr);
+  gap: 10px;
+  transform: translateY(100%);
+  transition: transform 0.25s var(--ease-out);
+}
+
+.bottom-nav__more-panel.is-open {
+  transform: translateY(0);
+}
+
+/* More panel item */
+.bottom-nav__more-item {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 6px;
+  padding: 12px 4px;
+  color: var(--text-dim);
+  text-decoration: none;
+  font-family: var(--font-body);
+  font-size: 11px;
+  font-weight: 500;
+  background: var(--surface);
+  border: 1px solid var(--border-line);
+  border-radius: var(--radius-md);
+  transition: color 0.18s var(--ease-out), border-color 0.18s var(--ease-out);
+  -webkit-tap-highlight-color: transparent;
+  cursor: pointer;
+}
+
+.bottom-nav__more-item:hover,
+.bottom-nav__more-item.is-active {
+  color: var(--neon-cyan);
+  border-color: var(--neon-cyan-dim);
+}
+
+.bottom-nav__more-item:hover .bottom-nav__icon,
+.bottom-nav__more-item.is-active .bottom-nav__icon {
+  filter: drop-shadow(0 0 6px var(--neon-cyan-dim));
+}
+
+/* Reduce motion */
+@media (prefers-reduced-motion: reduce) {
+  .bottom-nav__item,
+  .bottom-nav__icon,
+  .bottom-nav__more-overlay,
+  .bottom-nav__more-panel,
+  .bottom-nav__more-item {
+    transition: none;
+  }
+}