diff --git a/web/src/lib/components/champion-search.svelte b/web/src/lib/components/champion-search.svelte
new file mode 100644
index 0000000..59a69ba
--- /dev/null
+++ b/web/src/lib/components/champion-search.svelte
@@ -0,0 +1,122 @@
+<script>
+  import { getChampionImageUrl, searchChampions } from "$lib/champion-data";
+
+  /** Autocomplete search input for champion selection */
+  let { excludeNames, onSelect, disabled } = $props();
+
+  let query = $state("");
+  let activeIndex = $state(-1);
+  let isOpen = $state(false);
+  // $state because the dropdown is conditionally mounted, so bind:this
+  // reassigns these after the initial render.
+  let inputEl = $state();
+  let dropdownEl = $state();
+
+  let matches = $derived.by(() =>
+    query.trim() ? searchChampions(query, excludeNames) : [],
+  );
+
+  // Derived, never assigned from an effect — writing state that the same effect
+  // reads is the classic runes loop.
+  let isVisible = $derived(isOpen && matches.length > 0);
+
+  // Close dropdown on outside click. The element refs are read inside the
+  // handler, not during setup, so this registers once like the React effect did.
+  $effect(() => {
+    function handleClick(e) {
+      if (
+        inputEl &&
+        !inputEl.contains(e.target) &&
+        dropdownEl &&
+        !dropdownEl.contains(e.target)
+      ) {
+        isOpen = false;
+      }
+    }
+    document.addEventListener("mousedown", handleClick);
+    return () => document.removeEventListener("mousedown", handleClick);
+  });
+
+  function selectChampion(champion) {
+    query = "";
+    isOpen = false;
+    activeIndex = -1;
+    onSelect(champion);
+  }
+
+  function handleKeyDown(e) {
+    if (!isVisible || !matches.length) return;
+
+    if (e.key === "ArrowDown") {
+      e.preventDefault();
+      activeIndex = Math.min(activeIndex + 1, matches.length - 1);
+    } else if (e.key === "ArrowUp") {
+      e.preventDefault();
+      activeIndex = Math.max(activeIndex - 1, 0);
+    } else if (e.key === "Enter") {
+      e.preventDefault();
+      if (activeIndex >= 0 && activeIndex < matches.length) {
+        selectChampion(matches[activeIndex]);
+      }
+    } else if (e.key === "Escape") {
+      e.preventDefault();
+      isOpen = false;
+      activeIndex = -1;
+    }
+  }
+</script>
+
+<div class="relative w-full max-w-[400px] mx-auto px-4">
+  <input
+    bind:this={inputEl}
+    type="text"
+    role="combobox"
+    aria-expanded={isVisible}
+    aria-controls="champion-listbox"
+    aria-autocomplete="list"
+    aria-activedescendant={activeIndex >= 0
+      ? `champion-option-${activeIndex}`
+      : undefined}
+    bind:value={query}
+    oninput={() => {
+      activeIndex = -1;
+      isOpen = true;
+    }}
+    onkeydown={handleKeyDown}
+    {disabled}
+    placeholder={disabled ? "Game over" : "Type a champion name..."}
+    autocomplete="off"
+    class="w-full px-4 py-3 rounded-lg bg-[var(--color-input-bg)] border-2 border-[var(--color-input-border)] text-[var(--color-text)] text-base outline-none transition-colors focus:border-[var(--color-accent)] disabled:opacity-50 disabled:cursor-not-allowed placeholder:text-[var(--color-text-muted)]"
+  />
+
+  {#if isVisible}
+    <ul
+      bind:this={dropdownEl}
+      id="champion-listbox"
+      role="listbox"
+      class="absolute top-full left-4 right-4 list-none m-0 p-0 bg-[var(--color-surface)] border border-[var(--color-input-border)] rounded-b-lg max-h-80 overflow-y-auto z-50"
+    >
+      {#each matches as champion, i (champion.id)}
+        <li id="champion-option-{i}" role="option" aria-selected={i === activeIndex}>
+          <button
+            type="button"
+            onclick={() => selectChampion(champion)}
+            class="w-full text-left flex items-center gap-2.5 px-3 py-2 cursor-pointer transition-colors {i ===
+            activeIndex
+              ? 'bg-[var(--color-surface-hover)]'
+              : 'hover:bg-[var(--color-surface-hover)]'}"
+          >
+            <img
+              src={getChampionImageUrl(champion.id)}
+              alt={champion.name}
+              width="36"
+              height="36"
+              class="rounded object-cover"
+            />
+            <span class="text-sm">{champion.name}</span>
+          </button>
+        </li>
+      {/each}
+    </ul>
+  {/if}
+</div>
diff --git a/web/src/lib/components/game-board.svelte b/web/src/lib/components/game-board.svelte
new file mode 100644
index 0000000..c5989cd
--- /dev/null
+++ b/web/src/lib/components/game-board.svelte
@@ -0,0 +1,147 @@
+<script>
+  import { onMount } from "svelte";
+  import {
+    getRandomChampion,
+    getTodaySeed,
+    loadChampions,
+  } from "$lib/champion-data";
+  import { compareChampions } from "$lib/classic-mode";
+  import {
+    clearExpiredCache,
+    clearUnlimitedState,
+    createGame,
+    getOrCreateUnlimitedSeed,
+    loadUnlimitedStats,
+    saveUnlimitedStats,
+    submitGuess,
+  } from "$lib/game-engine";
+  import ChampionSearch from "./champion-search.svelte";
+  import GameOver from "./game-over.svelte";
+  import GuessGrid from "./guess-grid.svelte";
+  import StatsDisplay from "./stats-display.svelte";
+
+  let mode = $state("daily");
+  let game = $state(null);
+  let loading = $state(true);
+  let error = $state(null);
+  let stats = $state(null);
+
+  let excludeNames = $derived(game ? game.guesses.map((g) => g.name) : []);
+
+  function initGame(gameMode) {
+    const seed =
+      gameMode === "daily" ? getTodaySeed() : getOrCreateUnlimitedSeed();
+    const target = getRandomChampion(seed);
+    const maxGuesses = gameMode === "daily" ? 6 : 0;
+
+    game = createGame({
+      target,
+      compareFn: compareChampions,
+      maxGuesses,
+      mode: gameMode,
+      seed,
+    });
+    stats = gameMode === "unlimited" ? loadUnlimitedStats() : null;
+  }
+
+  // Browser-only and once-only by construction: the prerender pass has no
+  // localStorage and no champions.json to fetch.
+  onMount(async () => {
+    try {
+      await loadChampions();
+      clearExpiredCache(getTodaySeed());
+      initGame("daily");
+    } catch (err) {
+      error = err.message;
+    } finally {
+      loading = false;
+    }
+  });
+
+  function switchMode(newMode) {
+    mode = newMode;
+    initGame(newMode);
+  }
+
+  function handleGuess(champion) {
+    if (!game) return;
+
+    const updated = submitGuess(game, champion);
+    if (!updated) return;
+
+    // Always reassign — submitGuess returns new objects, so mutation would
+    // silently lose reactivity.
+    game = updated;
+
+    if (updated.isOver && updated.mode === "unlimited") {
+      saveUnlimitedStats(updated);
+      stats = loadUnlimitedStats();
+    }
+  }
+
+  function handleNewGame() {
+    clearUnlimitedState();
+    initGame("unlimited");
+  }
+</script>
+
+{#if loading}
+  <p class="text-center text-[var(--color-text-muted)] py-8">
+    Loading champions...
+  </p>
+{:else if error}
+  <p class="text-center text-[var(--color-wrong)] py-8">
+    Failed to load champion data. Please refresh.
+  </p>
+{:else if game}
+  <!-- Mode toggle -->
+  <div
+    class="flex justify-center gap-1 my-3 bg-[var(--color-surface)] rounded-lg p-1 w-fit mx-auto"
+  >
+    <button
+      onclick={() => switchMode("daily")}
+      class="px-5 py-2 rounded-md border-none text-sm font-medium cursor-pointer transition-all {mode ===
+      'daily'
+        ? 'bg-[var(--color-accent)] text-[var(--color-text)]'
+        : 'bg-transparent text-[var(--color-text-muted)] hover:text-[var(--color-text)] hover:bg-[var(--color-surface-hover)]'}"
+    >
+      Daily
+    </button>
+    <button
+      onclick={() => switchMode("unlimited")}
+      class="px-5 py-2 rounded-md border-none text-sm font-medium cursor-pointer transition-all {mode ===
+      'unlimited'
+        ? 'bg-[var(--color-accent)] text-[var(--color-text)]'
+        : 'bg-transparent text-[var(--color-text-muted)] hover:text-[var(--color-text)] hover:bg-[var(--color-surface-hover)]'}"
+    >
+      Unlimited
+    </button>
+  </div>
+
+  {#if stats}
+    <StatsDisplay {stats} />
+  {/if}
+
+  <ChampionSearch
+    {excludeNames}
+    onSelect={handleGuess}
+    disabled={game.isOver}
+  />
+
+  <p class="text-center text-[var(--color-text-muted)] text-sm my-3">
+    {game.maxGuesses > 0
+      ? `${game.guesses.length} / ${game.maxGuesses} guesses`
+      : `${game.guesses.length} guess${game.guesses.length !== 1 ? "es" : ""}`}
+  </p>
+
+  <GuessGrid guesses={game.guesses} results={game.results} />
+
+  {#if game.isOver}
+    <GameOver
+      isWon={game.isWon}
+      target={game.target}
+      guessCount={game.guesses.length}
+      onNewGame={mode === "unlimited" ? handleNewGame : undefined}
+    />
+  {/if}
+{/if}
diff --git a/web/src/lib/components/game-over.svelte b/web/src/lib/components/game-over.svelte
new file mode 100644
index 0000000..031bfdc
--- /dev/null
+++ b/web/src/lib/components/game-over.svelte
@@ -0,0 +1,46 @@
+<script>
+  import { getChampionImageUrl } from "$lib/champion-data";
+
+  /** Win/loss message with optional new game button */
+  let { isWon, target, guessCount, onNewGame } = $props();
+</script>
+
+<div class="text-center py-6 px-4 mx-auto max-w-[400px]">
+  <h2
+    class="text-2xl font-bold mb-2 {isWon
+      ? 'text-[var(--color-correct)]'
+      : 'text-[var(--color-wrong)]'}"
+  >
+    {isWon ? "You got it!" : "Game Over"}
+  </h2>
+
+  {#if isWon}
+    <p class="text-[var(--color-text-muted)] mb-3">
+      You found <strong class="text-[var(--color-text)]">{target.name}</strong> in
+      <strong class="text-[var(--color-text)]">{guessCount}</strong>
+      guess{guessCount > 1 ? "es" : ""}!
+    </p>
+  {:else}
+    <p class="text-[var(--color-text-muted)] mb-3">
+      The champion was <strong class="text-[var(--color-text)]"
+        >{target.name}</strong
+      >
+    </p>
+    <img
+      src={getChampionImageUrl(target.id)}
+      alt={target.name}
+      width="80"
+      height="80"
+      class="rounded-lg object-cover mx-auto"
+    />
+  {/if}
+
+  {#if onNewGame}
+    <button
+      onclick={onNewGame}
+      class="mt-4 px-6 py-2.5 rounded-lg bg-[var(--color-accent)] text-[var(--color-text)] font-semibold cursor-pointer transition-opacity hover:opacity-85"
+    >
+      New Game
+    </button>
+  {/if}
+</div>
diff --git a/web/src/lib/components/guess-grid.svelte b/web/src/lib/components/guess-grid.svelte
new file mode 100644
index 0000000..bd5a112
--- /dev/null
+++ b/web/src/lib/components/guess-grid.svelte
@@ -0,0 +1,28 @@
+<script>
+  import { CLASSIC_ATTRIBUTES } from "$lib/classic-mode";
+  import GuessRow from "./guess-row.svelte";
+
+  /** Grid with header row + guess rows */
+  let { guesses, results } = $props();
+
+  // Newest guess first. .reverse() acts on the fresh array from .map(),
+  // so `guesses` itself is never mutated.
+  let rows = $derived(
+    guesses.map((champion, i) => ({ champion, results: results[i] })).reverse(),
+  );
+</script>
+
+<div class="w-full max-w-[900px] px-4 overflow-x-auto">
+  <!-- Header row -->
+  <div class="guess-row header-row">
+    <div class="guess-cell header-cell">Champion</div>
+    {#each CLASSIC_ATTRIBUTES as attr (attr.key)}
+      <div class="guess-cell header-cell">{attr.label}</div>
+    {/each}
+  </div>
+
+  <!-- Guess rows — newest first -->
+  {#each rows as row (row.champion.id)}
+    <GuessRow champion={row.champion} results={row.results} />
+  {/each}
+</div>
diff --git a/web/src/lib/components/guess-row.svelte b/web/src/lib/components/guess-row.svelte
new file mode 100644
index 0000000..7e7912c
--- /dev/null
+++ b/web/src/lib/components/guess-row.svelte
@@ -0,0 +1,35 @@
+<script>
+  import { getChampionImageUrl } from "$lib/champion-data";
+
+  /** Single guess row with colored attribute cells */
+  let { champion, results } = $props();
+</script>
+
+<div class="guess-row">
+  <!-- Champion name + image -->
+  <div class="guess-cell champion-cell" style="animation-delay: 0s">
+    <img
+      src={getChampionImageUrl(champion.id)}
+      alt={champion.name}
+      width="40"
+      height="40"
+      class="rounded object-cover shrink-0"
+    />
+    <span class="text-xs font-semibold">{champion.name}</span>
+  </div>
+
+  <!-- Attribute cells: the within-row reveal stagger -->
+  {#each results as r, i (r.key)}
+    <div
+      class="guess-cell cell-{r.result}"
+      style="animation-delay: {(i + 1) * 0.08}s"
+    >
+      <span>{r.guessValue}</span>
+      {#if r.direction}
+        <span class="font-bold text-base">
+          {r.direction === "up" ? " ↑" : " ↓"}
+        </span>
+      {/if}
+    </div>
+  {/each}
+</div>
diff --git a/web/src/lib/components/stats-display.svelte b/web/src/lib/components/stats-display.svelte
new file mode 100644
index 0000000..51ff7c4
--- /dev/null
+++ b/web/src/lib/components/stats-display.svelte
@@ -0,0 +1,29 @@
+<script>
+  /** Unlimited mode stats display */
+  let { stats } = $props();
+
+  let winRate = $derived(
+    stats && stats.gamesPlayed
+      ? Math.round((stats.gamesWon / stats.gamesPlayed) * 100)
+      : 0,
+  );
+
+  let items = $derived([
+    { value: stats?.gamesPlayed, label: "Played" },
+    { value: `${winRate}%`, label: "Win Rate" },
+    { value: stats?.gamesWon, label: "Won" },
+  ]);
+</script>
+
+{#if stats && stats.gamesPlayed > 0}
+  <div class="flex justify-center gap-6 py-3 mb-4">
+    {#each items as { value, label } (label)}
+      <div class="flex flex-col items-center gap-0.5">
+        <span class="text-xl font-bold text-[var(--color-text)]">{value}</span>
+        <span class="text-[0.7rem] text-[var(--color-text-muted)] uppercase"
+          >{label}</span
+        >
+      </div>
+    {/each}
+  </div>
+{/if}
diff --git a/web/src/routes/+page.svelte b/web/src/routes/+page.svelte
index bbf213e..28dbcda 100644
--- a/web/src/routes/+page.svelte
+++ b/web/src/routes/+page.svelte
@@ -1,9 +1,12 @@
-<!-- Placeholder: header only, so the build is verifiable before components exist.
-     Phase 4 mounts the real game board here. -->
+<script>
+  import GameBoard from "$lib/components/game-board.svelte";
+</script>
+
 <main class="flex flex-col items-center min-h-screen">
   <header class="text-center pt-6 pb-2 w-full max-w-[900px]">
     <h1 class="text-3xl font-bold tracking-wider">
       Lo<span class="text-[var(--color-accent)]">L</span>dle
     </h1>
   </header>
+  <GameBoard />
 </main>