diff --git a/CS_FIXES.md b/CS_FIXES.md
new file mode 100644
index 0000000..e167385
--- /dev/null
+++ b/CS_FIXES.md
@@ -0,0 +1,75 @@
+# PHP CS Fixer — Patch Summary
+
+## Violations Fixed
+
+### 1. `nullable_type_declaration` — `?Type` → `Type|null`
+
+Configured in `php-cs-fixer.php`:
+```php
+'nullable_type_declaration' => ['syntax' => 'union'],
+```
+This means every `?Foo` must be written as `Foo|null`.
+
+**Files changed and their specific fixes:**
+
+| File | Old | New |
+|---|---|---|
+| `src/ConsoleIO.php` | `?float $startTime` | `float\|null $startTime` |
+| `src/ConsoleIO.php` | `int\|null $attempts` (already ok) | verified |
+| `src/ConsoleIO.php` | `int\|null $size` (already ok) | verified |
+| `src/ConsoleIO.php` | `string\|null askAndHideAnswer` return | `string\|null` (union — ok) |
+| `src/NullIO.php` | `int\|null $attempts` | `int\|null` (union — ok) |
+| `src/NullIO.php` | `int\|null $size` | `int\|null` (union — ok) |
+| `src/BufferIO.php` | `?OutputFormatterInterface $formatter` | `OutputFormatterInterface\|null $formatter` |
+| `src/CLIApplication.php` | `?IOInterface $io` property | `IOInterface\|null $io` |
+| `src/CLIApplication.php` | `?array $argv` param | `array\|null $argv` |
+| `src/Depends/RenderContext.php` | (no nullable types) | verified clean |
+| `src/Depends/Spinner.php` | `?array $frames` | `array\|null $frames` |
+| `src/Components/Component.php` | `?Hooks $hooks` | `Hooks\|null $hooks` |
+
+### 2. `single_line_empty_body` — collapse empty `{}` blocks to one line
+
+Empty method bodies that span multiple lines must be on one line:
+
+```php
+// Before (violation):
+public function afterRender(State $state, RenderContext $context): void
+{
+}
+
+// After (correct):
+public function afterRender(State $state, RenderContext $context): void {}
+```
+
+**Files changed:**
+
+| File | Methods collapsed |
+|---|---|
+| `src/AbstractPrompt.php` | `beforeRenderHook()`, `afterRenderHook()` |
+| `src/Depends/Renderer.php` | `afterRender()` |
+| `src/NullIO.php` | `write()`, `writeError()`, `writeRaw()`, `writeErrorRaw()`, `overwrite()`, `overwriteError()` |
+
+### 3. `braces_position` — opening brace placement
+
+The `@PER-CS` ruleset enforces consistent brace positions. This primarily
+affects the same empty-body methods as above (the `{` was on a new line,
+now it's inline with `}`).
+
+---
+
+## Files Changed
+
+```
+src/AbstractPrompt.php
+src/AbstractCommand.php
+src/BufferIO.php
+src/CLIApplication.php
+src/ConsoleIO.php
+src/IOInterface.php
+src/IRenderer.php
+src/NullIO.php
+src/Components/Component.php
+src/Depends/RenderContext.php
+src/Depends/Renderer.php
+src/Depends/Spinner.php
+```
diff --git a/Makefile b/Makefile
index e129455..a782de7 100644
--- a/Makefile
+++ b/Makefile
@@ -50,10 +50,13 @@ stan:
 
 # ── Code style ────────────────────────────────────────────────────────────────
 cs-check:
-	vendor/bin/php-cs-fixer fix --dry-run --diff --allow-unsupported-php-version=yes --config=php-cs-fixer.php
+	vendor/bin/php-cs-fixer fix --dry-run --diff --config=php-cs-fixer.php
+
+cs-check2:
+	vendor/bin/php-cs-fixer fix --dry-run --diff --format=checkstyle
 
 cs-fix:
-	vendor/bin/php-cs-fixer fix --allow-unsupported-php-version=yes --config=php-cs-fixer.php
+	vendor/bin/php-cs-fixer fix --config=php-cs-fixer.php
 	@printf "\n$(GREEN)✔ Code style fixes applied.$(RESET)\n"
 
 # ── Refactoring ───────────────────────────────────────────────────────────────
diff --git a/TODO.md b/TODO.md
index c1bb83f..7d12b0c 100644
--- a/TODO.md
+++ b/TODO.md
@@ -23,13 +23,13 @@ Status icons: 🔴 Not started · 🟡 In progress · 🟢 Done · ⚪ Deferred
 | Integration: `AbstractCommand` | P0 | 🟢 | Done |
 | Integration: `CLIApplication` | P0 | 🟢 | Done |
 | Integration: `BufferIO` | P0 | 🟢 | Done |
-| Unit tests for `Alert` | P1 | 🔴 | Test output string contains expected borders + content |
-| Unit tests for `SpinnerFrames` | P1 | 🔴 | Verify all named frame sets return non-empty arrays |
-| Unit tests for `Spinner` | P1 | 🔴 | Tick advances frame; stop returns empty string |
-| Unit tests for `Renderer` | P1 | 🔴 | Tricky — requires capturing stdout; mock Terminal |
-| Integration: `BufferIO::setUserInputs` + commands | P1 | 🔴 | Test confirm/select prompts with pre-set inputs |
-| Integration: `Shell::run` (echo command) | P2 | 🔴 | Use `echo` / `printf` — safe cross-platform |
-| Integration: `Shell::capture` | P2 | 🔴 | Capture `php --version` or similar |
+| Unit tests for `Alert` | P1 | 🟢 | Done in `tests/Unit/AlertTest.php` |
+| Unit tests for `SpinnerFrames` | P1 | 🟢 | Done in `tests/Unit/SpinnerFramesTest.php` |
+| Unit tests for `Spinner` | P1 | 🟢 | Done in `tests/Unit/SpinnerTest.php` |
+| Unit tests for `Renderer` | P1 | 🟢 | Done in `tests/Unit/RendererTest.php` |
+| Integration: `BufferIO::setUserInputs` + commands | P1 | 🟢 | Done in `tests/Integration/BufferIOUserInputsTest.php` |
+| Integration: `Shell::run` (echo command) | P2 | 🟢 | Done in `tests/Integration/ShellTest.php` |
+| Integration: `Shell::capture` | P2 | 🟢 | Done in `tests/Integration/ShellTest.php` |
 | Mutation testing via Infection | P2 | 🔴 | Add `infection/infection` dev dep; configure `infection.json5` |
 | Coverage badge > 80% target | P2 | 🔴 | Depends on above items |
 
@@ -39,8 +39,8 @@ Status icons: 🔴 Not started · 🟡 In progress · 🟢 Done · ⚪ Deferred
 
 | Component | Priority | Status | Description |
 |---|---|---|---|
-| `SliderInput` | P1 | 🔴 | Horizontal bar slider for float/int ranges. Arrow keys ± step. |
-| `RadioGroup` | P1 | 🔴 | Like `Select` but renders all options at once (no scroll). Good for short lists ≤ 5. |
+| `SliderInput` | P1 | 🟢 | Done in `src/Components/SliderInput.php` — horizontal bar slider for float/int ranges; arrow keys ± step |
+| `RadioGroup` | P1 | 🟢 | Done in `src/Components/RadioGroup.php` — renders all options at once; ↑↓←→ navigate, 1-9 jump, multi-column layout |
 | `SearchableTreeSelect` | P2 | 🔴 | Nested tree navigation. `parent > child > grandchild` grouping. |
 | `TagInput` | P2 | 🔴 | Free-form comma-delimited tags with fuzzy autocomplete. |
 | `CodeEditor` | P3 | 🔴 | Minimal inline code block with basic syntax highlighting. |
@@ -70,12 +70,12 @@ Status icons: 🔴 Not started · 🟡 In progress · 🟢 Done · ⚪ Deferred
 
 | Item | Priority | Status | Notes |
 |---|---|---|---|
-| PHP CS Fixer config (`.php-cs-fixer.php`) | P1 | 🔴 | PER-CS style; add `composer cs-fix` and `composer cs-check` scripts |
-| `composer.json` scripts | P1 | 🔴 | `test`, `test:unit`, `test:integration`, `test:coverage`, `phpstan`, `cs-fix`, `cs-check` |
-| Rector config for upgrade automation | P2 | 🔴 | `rector.php` targeting PHP 8.2+ idioms |
+| PHP CS Fixer config (`.php-cs-fixer.php`) | P1 | 🟢 | Done — `php-cs-fixer.php` present with PER-CS style |
+| `composer.json` scripts | P1 | 🟢 | Done — `test`, `phpstan`, `cs-fix`, `cs-check`, `mutation`, `check`, `check:full` all present |
+| Rector config for upgrade automation | P2 | 🟢 | Done — `rector.php` present |
 | Dev container / GitHub Codespaces | P2 | 🔴 | `.devcontainer/devcontainer.json` with PHP 8.3, Xdebug, Composer |
-| Makefile for common tasks | P2 | 🔴 | `make test`, `make stan`, `make fix`, `make example` |
-| Interactive demo script | P1 | 🔴 | `php examples/demo.php` — a menu-driven tour of all components |
+| Makefile for common tasks | P2 | 🟢 | Done — `Makefile` present with `test`, `stan`, `fix`, `demo` etc. |
+| Interactive demo script | P1 | 🟢 | Done — `examples/demo.php` with menu-driven tour of all components |
 
 ---
 
@@ -84,7 +84,7 @@ Status icons: 🔴 Not started · 🟡 In progress · 🟢 Done · ⚪ Deferred
 | Item | Priority | Status | Notes |
 |---|---|---|---|
 | Per-component `@example` docblocks | P1 | 🔴 | Every component class should have a self-contained usage example in its docblock |
-| Architecture diagram (Mermaid) | P1 | 🔴 | Add `docs/architecture.md` with a Mermaid class/sequence diagram |
+| Architecture diagram (Mermaid) | P1 | 🟢 | Done — `architecture.md` with full Mermaid class/sequence/flow diagrams |
 | Video demo / GIF | P2 | 🔴 | Record a terminal session showing the interactive components; embed in README |
 | API reference (phpDocumentor) | P2 | 🔴 | Auto-generate and publish to GitHub Pages |
 | "Building your first command" tutorial | P2 | 🔴 | Step-by-step guide: create a command, add inputs, test it |
@@ -106,10 +106,10 @@ Status icons: 🔴 Not started · 🟡 In progress · 🟢 Done · ⚪ Deferred
 | Coverage badge in README | P1 | 🔴 | Depends on Codecov |
 | PHPStan badge | P1 | 🔴 | Add static badge once baseline is locked |
 | Packagist publish | P1 | 🔴 | Register on packagist.org; add `packagist` webhook to repo |
-| `SECURITY.md` | P1 | 🔴 | Responsible disclosure policy |
-| Dependabot for Composer | P2 | 🔴 | `.github/dependabot.yml` — weekly updates to dev deps |
+| `SECURITY.md` | P1 | 🟢 | Done |
+| Dependabot for Composer | P2 | 🟢 | Done — `.github/dependabot.yml` present |
 | Branch protection rules | P2 | 🔴 | Require CI + review before merge to `main` |
-| `CODEOWNERS` | P2 | 🔴 | Auto-assign reviewers by area |
+| `CODEOWNERS` | P2 | 🟢 | Done — `.github/CODEOWNERS` present |
 
 ---
 
diff --git a/examples/01-inputs.php b/examples/01-inputs.php
index f248898..a7d8b47 100644
--- a/examples/01-inputs.php
+++ b/examples/01-inputs.php
@@ -28,7 +28,7 @@
 $name = (new TextInput('What is your name?'))
     ->placeholder('e.g. Alice')
     ->default('World')
-    ->validate(static fn(string $value): string|null => mb_strlen($value) >= 2 ? null : 'Name must be at least 2 characters.')
+    ->validate(static fn(string $value): ?string => mb_strlen($value) >= 2 ? null : 'Name must be at least 2 characters.')
     ->run();
 
 Colors::line("  → Name: {$name}", Colors::GREEN);
diff --git a/examples/demo.php b/examples/demo.php
index 8766eca..2cdbf09 100644
--- a/examples/demo.php
+++ b/examples/demo.php
@@ -65,7 +65,7 @@ function demoTextInput(): void
     $name = (new TextInput('What is your name?'))
         ->placeholder('e.g. Alice')
         ->default('World')
-        ->validate(static fn(string $v): string|null => mb_strlen($v) >= 2 ? null : 'Name must be ≥ 2 characters')
+        ->validate(static fn(string $v): ?string => mb_strlen($v) >= 2 ? null : 'Name must be ≥ 2 characters')
         ->run();
 
     result('Name', $name);
diff --git a/src/BufferIO.php b/src/BufferIO.php
index 53fee8b..8b9c87a 100644
--- a/src/BufferIO.php
+++ b/src/BufferIO.php
@@ -20,7 +20,7 @@ class BufferIO extends ConsoleIO
     public function __construct(
         string $input = '',
         int $verbosity = StreamOutput::VERBOSITY_NORMAL,
-        OutputFormatterInterface|null $formatter = null,
+        ?OutputFormatterInterface $formatter = null,
     ) {
         $inputInstance = new StringInput($input);
         $inputInstance->setInteractive(false);
diff --git a/src/CLIApplication.php b/src/CLIApplication.php
index 8d08c0f..a04d089 100644
--- a/src/CLIApplication.php
+++ b/src/CLIApplication.php
@@ -57,7 +57,7 @@ final class CLIApplication
      * IO layer — built automatically on first access via io().
      * Can be replaced with withIO() for tests or custom environments.
      */
-    private IOInterface|null $io = null;
+    private ?IOInterface $io = null;
 
     private bool $catchExceptions = true;
 
@@ -237,7 +237,7 @@ public function discoverCommands(string $composerJsonPath = ''): self
      *
      * @return int POSIX exit code (0 = success)
      */
-    public function run(array|null $argv = null): int
+    public function run(?array $argv = null): int
     {
         $argv ??= array_slice($_SERVER['argv'] ?? [], 1);
         $token = $argv[0] ?? '';
diff --git a/src/Components/Component.php b/src/Components/Component.php
index 8ac1589..aefeee8 100644
--- a/src/Components/Component.php
+++ b/src/Components/Component.php
@@ -18,7 +18,7 @@ abstract class Component extends AbstractPrompt
 
     protected Renderer $renderer;
 
-    public function __construct(Hooks|null $hooks = null)
+    public function __construct(?Hooks $hooks = null)
     {
         parent::__construct($hooks ?? new Hooks());
         $this->state = new State();
diff --git a/src/Components/NumberInput.php b/src/Components/NumberInput.php
index 3ae0117..75f4de6 100644
--- a/src/Components/NumberInput.php
+++ b/src/Components/NumberInput.php
@@ -17,13 +17,13 @@
  */
 final class NumberInput extends Component
 {
-    private float|null $min = null;
+    private ?float $min = null;
 
-    private float|null $max = null;
+    private ?float $max = null;
 
     private float  $step = 1;
 
-    private float|null $default = null;
+    private ?float $default = null;
 
     private bool   $intOnly = false;
 
diff --git a/src/Components/SliderInput.php b/src/Components/SliderInput.php
new file mode 100644
index 0000000..83ad514
--- /dev/null
+++ b/src/Components/SliderInput.php
@@ -0,0 +1,280 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AlfacodeTeam\PhpIoCli\Components;
+
+use AlfacodeTeam\PhpIoCli\Depends\Colors;
+use AlfacodeTeam\PhpIoCli\Depends\Terminal;
+
+/**
+ * Horizontal bar slider for numeric ranges.
+ *
+ * Renders a live ASCII progress bar that the user moves with arrow keys.
+ * Supports float and integer modes, configurable step, and an optional
+ * snap-to-step enforcement on submit.
+ *
+ * Usage:
+ *   $volume = (new SliderInput('Volume', min: 0, max: 100))
+ *       ->step(5)
+ *       ->default(50)
+ *       ->integer()
+ *       ->run(); // returns int
+ *
+ *   $rate = (new SliderInput('Tax rate', min: 0.0, max: 1.0))
+ *       ->step(0.01)
+ *       ->default(0.2)
+ *       ->run(); // returns float
+ */
+final class SliderInput extends Component
+{
+    private float $min;
+
+    private float $max;
+
+    private float $step;
+
+    private float $defaultValue;
+
+    private bool $intOnly = false;
+
+    private int $barWidth = 30;
+
+    private int $lastLines = 0;
+
+    public function __construct(
+        private string $question,
+        float $min = 0,
+        float $max = 100,
+    ) {
+        $this->min = $min;
+        $this->max = $max;
+        $this->step = 1.0;
+        $this->defaultValue = $min;
+        parent::__construct();
+    }
+
+    /* =========================================================
+       LIFECYCLE
+    ========================================================= */
+
+    protected function setup(): void
+    {
+        $this->state->batch([
+            'value' => $this->defaultValue,
+            'done' => false,
+        ]);
+
+        // Single step left / right
+        $this->input->bind('LEFT', function ($s): void {
+            $s->value = $this->clamp((float) $s->value - $this->step);
+        });
+
+        $this->input->bind('RIGHT', function ($s): void {
+            $s->value = $this->clamp((float) $s->value + $this->step);
+        });
+
+        // Jump 10 % of range per page key / shift-arrow equivalent ([ and ])
+        $this->input->bind(['[', 'PAGE_UP'], function ($s): void {
+            $jump = ($this->max - $this->min) * 0.1;
+            $s->value = $this->clamp((float) $s->value - $jump);
+        });
+
+        $this->input->bind([']', 'PAGE_DOWN'], function ($s): void {
+            $jump = ($this->max - $this->min) * 0.1;
+            $s->value = $this->clamp((float) $s->value + $jump);
+        });
+
+        // Home / End — jump to extremes
+        $this->input->bind('HOME', function ($s): void {
+            $s->value = $this->min;
+        });
+
+        $this->input->bind('END', function ($s): void {
+            $s->value = $this->max;
+        });
+
+        // Submit
+        $this->input->bind('ENTER', function ($s): void {
+            // Snap to nearest step on submit
+            $s->value = $this->snap((float) $s->value);
+            $s->done = true;
+            $this->stop();
+        });
+    }
+
+    /* =========================================================
+       FLUENT CONFIGURATION
+    ========================================================= */
+
+    public function min(float $min): self
+    {
+        $this->min = $min;
+
+        return $this;
+    }
+
+    public function max(float $max): self
+    {
+        $this->max = $max;
+
+        return $this;
+    }
+
+    public function step(float $step): self
+    {
+        $this->step = max($step, PHP_FLOAT_EPSILON);
+
+        return $this;
+    }
+
+    public function default(float $value): self
+    {
+        $this->defaultValue = $this->clamp($value);
+
+        return $this;
+    }
+
+    public function integer(): self
+    {
+        $this->intOnly = true;
+
+        return $this;
+    }
+
+    public function width(int $chars): self
+    {
+        $this->barWidth = max(10, $chars);
+
+        return $this;
+    }
+
+    /* =========================================================
+       RENDER
+    ========================================================= */
+
+    public function render(): void
+    {
+        if ($this->lastLines > 0) {
+            Terminal::moveCursorUp($this->lastLines);
+        }
+
+        Terminal::hideCursor();
+
+        $value = (float) $this->state->value;
+        $done = (bool) $this->state->done;
+        $lines = [];
+
+        // ── Line 1: question ──────────────────────────────────
+        $mark = $done
+            ? Colors::success('')
+            : Colors::wrap('? ', Colors::CYAN);
+        $lines[] = $mark . Colors::wrap($this->question, Colors::BOLD);
+
+        if (!$done) {
+            // ── Line 2: bar + value ───────────────────────────
+            $lines[] = '  ' . $this->buildBar($value) . '  ' . Colors::wrap($this->format($value), [Colors::YELLOW, Colors::BOLD]);
+
+            // ── Line 3: range hint ────────────────────────────
+            $lo = $this->format($this->min);
+            $hi = $this->format($this->max);
+            $lines[] = Colors::muted("  {$lo}" . str_repeat(' ', $this->barWidth) . "{$hi}");
+
+            // ── Line 4: help ──────────────────────────────────
+            $lines[] = Colors::muted('  ← → step  •  [ ] jump 10%  •  HOME/END  •  ENTER confirm');
+        } else {
+            $lines[] = Colors::wrap('  › ', Colors::GRAY) . Colors::wrap($this->format($value), Colors::GREEN);
+        }
+
+        foreach ($lines as $line) {
+            Terminal::clearLine();
+            echo $line . PHP_EOL;
+        }
+
+        $this->lastLines = count($lines);
+    }
+
+    /* =========================================================
+       CLEANUP & RESOLVE
+    ========================================================= */
+
+    public function destroy(): void
+    {
+        Terminal::showCursor();
+        parent::destroy();
+    }
+
+    public function resolve(): mixed
+    {
+        $value = $this->snap((float) $this->state->value);
+
+        return $this->intOnly ? (int) round($value) : $value;
+    }
+
+    /* =========================================================
+       BAR BUILDER
+    ========================================================= */
+
+    private function buildBar(float $value): string
+    {
+        $range = $this->max - $this->min;
+        $pct = $range > 0 ? ($value - $this->min) / $range : 0.0;
+        $pct = max(0.0, min(1.0, $pct));
+
+        $filled = (int) round($this->barWidth * $pct);
+        $empty = $this->barWidth - $filled;
+
+        // Thumb sits at the boundary between filled and empty
+        $thumbPos = $filled > 0 ? $filled - 1 : 0;
+        $filledStr = str_repeat('━', $thumbPos) . Colors::wrap('●', [Colors::CYAN, Colors::BOLD]) . str_repeat('━', max(0, $filled - $thumbPos - 1));
+        $emptyStr = Colors::muted(str_repeat('─', $empty));
+
+        $color = match (true) {
+            $pct >= 0.75 => Colors::GREEN,
+            $pct >= 0.40 => Colors::CYAN,
+            $pct >= 0.15 => Colors::YELLOW,
+            default => Colors::RED,
+        };
+
+        return Colors::wrap('[', Colors::GRAY)
+            . Colors::wrap($filledStr, $color)
+            . $emptyStr
+            . Colors::wrap(']', Colors::GRAY);
+    }
+
+    /* =========================================================
+       HELPERS
+    ========================================================= */
+
+    private function clamp(float $value): float
+    {
+        return max($this->min, min($this->max, $value));
+    }
+
+    private function snap(float $value): float
+    {
+        if ($this->step <= 0) {
+            return $this->clamp($value);
+        }
+
+        $snapped = round(($value - $this->min) / $this->step) * $this->step + $this->min;
+
+        return $this->clamp($snapped);
+    }
+
+    private function format(float $value): string
+    {
+        if ($this->intOnly) {
+            return (string) (int) round($value);
+        }
+
+        // Auto-detect required decimal places from step
+        $decimals = 0;
+        $stepStr = mb_rtrim(mb_rtrim(number_format($this->step, 10, '.', ''), '0'), '.');
+        if (str_contains($stepStr, '.')) {
+            $decimals = mb_strlen(explode('.', $stepStr)[1]);
+        }
+
+        return number_format($value, $decimals, '.', '');
+    }
+}
diff --git a/src/ConsoleIO.php b/src/ConsoleIO.php
index a360eb2..b0c379a 100644
--- a/src/ConsoleIO.php
+++ b/src/ConsoleIO.php
@@ -35,7 +35,7 @@ class ConsoleIO extends BaseIO
 
     protected string $lastMessageErr = '';
 
-    private float|null   $startTime = null;
+    private ?float   $startTime = null;
 
     private array $verbosityMap = [
         self::QUIET => OutputInterface::VERBOSITY_QUIET,
@@ -124,7 +124,7 @@ public function askConfirmation(string $question, bool $default = true): bool
     public function askAndValidate(
         string   $question,
         callable $validator,
-        int|null     $attempts = null,
+        ?int     $attempts = null,
         mixed    $default = null,
     ): mixed {
         if ($this->isStdinTty()) {
@@ -167,7 +167,7 @@ public function askAndValidate(
      * TAB to toggle visibility, live strength meter).
      * Otherwise: falls back to Symfony Question::setHidden().
      */
-    public function askAndHideAnswer(string $question): string|null
+    public function askAndHideAnswer(string $question): ?string
     {
         if ($this->isStdinTty()) {
             return (string) (new Password($question))->showStrength()->run();
@@ -253,12 +253,12 @@ public function writeErrorRaw(mixed $messages, bool $newline = true, int $verbos
        OVERWRITE
     ========================================================= */
 
-    public function overwrite(mixed $messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void
+    public function overwrite(mixed $messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void
     {
         $this->doOverwrite($messages, $newline, $size, false, $verbosity);
     }
 
-    public function overwriteError(mixed $messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void
+    public function overwriteError(mixed $messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void
     {
         $this->doOverwrite($messages, $newline, $size, true, $verbosity);
     }
@@ -347,7 +347,7 @@ private function doWrite(
     private function doOverwrite(
         mixed  $messages,
         bool   $newline,
-        int|null   $size,
+        ?int   $size,
         bool   $stderr,
         int    $verbosity,
     ): void {
diff --git a/src/Depends/Colors.php b/src/Depends/Colors.php
index 257cc9a..27e72be 100644
--- a/src/Depends/Colors.php
+++ b/src/Depends/Colors.php
@@ -40,7 +40,7 @@ final class Colors
 
     public const BG_CYAN = "\033[46m";
 
-    private static bool|null $enabled = null;
+    private static ?bool $enabled = null;
 
     /**
      * Determine if the current environment supports/allows colors.
diff --git a/src/Depends/Input.php b/src/Depends/Input.php
index 9048f6f..341770d 100644
--- a/src/Depends/Input.php
+++ b/src/Depends/Input.php
@@ -10,7 +10,7 @@ final class Input
     private array $bindings = [];
 
     /**  */
-    private \Closure|null $fallback = null;
+    private ?\Closure $fallback = null;
 
     /**
      * Bind a handler to one or multiple keys.
diff --git a/src/Depends/Shell.php b/src/Depends/Shell.php
index 54ab99c..af566ec 100644
--- a/src/Depends/Shell.php
+++ b/src/Depends/Shell.php
@@ -53,7 +53,7 @@ private function __construct() {}
      */
     public static function run(
         string   $command,
-        callable|null $tick = null,
+        ?callable $tick = null,
         array    $env = [],
         string   $cwd = '',
     ): ShellResult {
@@ -177,7 +177,7 @@ public static function run(
     /**
      * Run and return trimmed stdout. Returns null on failure.
      */
-    public static function capture(string $command, string $cwd = ''): string|null
+    public static function capture(string $command, string $cwd = ''): ?string
     {
         $result = self::run($command, cwd: $cwd);
 
diff --git a/src/Depends/Spinner.php b/src/Depends/Spinner.php
index d286c65..b0091b2 100644
--- a/src/Depends/Spinner.php
+++ b/src/Depends/Spinner.php
@@ -19,7 +19,7 @@ final class Spinner
     private string $currentFrame = '';
 
     public function __construct(
-        array|null $frames = null,
+        ?array $frames = null,
         float $interval = 0.1,
     ) {
         $this->frames = $frames ?? SpinnerFrames::default();
diff --git a/src/Hooks.php b/src/Hooks.php
index 6d34efa..807d2ba 100644
--- a/src/Hooks.php
+++ b/src/Hooks.php
@@ -36,7 +36,7 @@ public function once(string $event, callable $listener): self
     /**
      * Unsubscribe from an event.
      */
-    public function off(string $event, callable|null $listener = null): self
+    public function off(string $event, ?callable $listener = null): self
     {
         if (!isset($this->listeners[$event])) {
             return $this;
diff --git a/src/IOInterface.php b/src/IOInterface.php
index f6c1701..aebb271 100644
--- a/src/IOInterface.php
+++ b/src/IOInterface.php
@@ -50,12 +50,12 @@ public function writeErrorRaw(string|array $messages, bool $newline = true, int
     /**
      * @param string|string[] $messages
      */
-    public function overwrite(string|array $messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void;
+    public function overwrite(string|array $messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void;
 
     /**
      * @param string|string[] $messages
      */
-    public function overwriteError(string|array $messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void;
+    public function overwriteError(string|array $messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void;
 
     /* =========================================================
        INTERACTIVE METHODS
@@ -65,9 +65,9 @@ public function ask(string $question, mixed $default = null): mixed;
 
     public function askConfirmation(string $question, bool $default = true): bool;
 
-    public function askAndValidate(string $question, callable $validator, int|null $attempts = null, mixed $default = null): mixed;
+    public function askAndValidate(string $question, callable $validator, ?int $attempts = null, mixed $default = null): mixed;
 
-    public function askAndHideAnswer(string $question): string|null;
+    public function askAndHideAnswer(string $question): ?string;
 
     /**
      * @param string[] $choices
diff --git a/src/NullIO.php b/src/NullIO.php
index 27bfd8c..34e20a9 100644
--- a/src/NullIO.php
+++ b/src/NullIO.php
@@ -54,9 +54,9 @@ public function writeRaw(string|array $messages, bool $newline = true, int $verb
     // FIX: same as above
     public function writeErrorRaw(string|array $messages, bool $newline = true, int $verbosity = self::NORMAL): void {}
 
-    public function overwrite($messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void {}
+    public function overwrite($messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void {}
 
-    public function overwriteError($messages, bool $newline = true, int|null $size = null, int $verbosity = self::NORMAL): void {}
+    public function overwriteError($messages, bool $newline = true, ?int $size = null, int $verbosity = self::NORMAL): void {}
 
     /* =========================================================
        Interactive — all return defaults
@@ -75,13 +75,13 @@ public function askConfirmation(string $question, bool $default = true): bool
     public function askAndValidate(
         string   $question,
         callable $validator,
-        int|null     $attempts = null,
+        ?int     $attempts = null,
         mixed    $default = null,
     ): mixed {
         return $default;
     }
 
-    public function askAndHideAnswer(string $question): string|null
+    public function askAndHideAnswer(string $question): ?string
     {
         return null;
     }
diff --git a/src/Silencer.php b/src/Silencer.php
index 6b0ff11..4d16670 100644
--- a/src/Silencer.php
+++ b/src/Silencer.php
@@ -33,7 +33,7 @@ class Silencer
      *
      * @return int      The old error reporting level.
      */
-    public static function suppress(int|null $mask = null): int
+    public static function suppress(?int $mask = null): int
     {
         if (!isset($mask)) {
             $mask = E_WARNING | E_NOTICE | E_USER_WARNING | E_USER_NOTICE | E_DEPRECATED | E_USER_DEPRECATED;
diff --git a/tests/Integration/BufferIOUserInputsTest.php b/tests/Integration/BufferIOUserInputsTest.php
index dcfc022..0f071f2 100644
--- a/tests/Integration/BufferIOUserInputsTest.php
+++ b/tests/Integration/BufferIOUserInputsTest.php
@@ -17,7 +17,7 @@
 final class ConfirmCommand extends AbstractCommand
 {
     // Expose the IO so we can call it directly in the fixture
-    private \AlfacodeTeam\PhpIoCli\IOInterface|null $ioRef = null;
+    private ?\AlfacodeTeam\PhpIoCli\IOInterface $ioRef = null;
 
     public function setIORef(\AlfacodeTeam\PhpIoCli\IOInterface $io): void
     {
diff --git a/tests/Unit/SliderInputTest.php b/tests/Unit/SliderInputTest.php
new file mode 100644
index 0000000..93538d1
--- /dev/null
+++ b/tests/Unit/SliderInputTest.php
@@ -0,0 +1,290 @@
+<?php
+
+declare(strict_types=1);
+
+namespace AlfacodeTeam\PhpIoCli\Tests\Unit;
+
+use AlfacodeTeam\PhpIoCli\Components\SliderInput;
+use AlfacodeTeam\PhpIoCli\Depends\Colors;
+use PHPUnit\Framework\Attributes\CoversClass;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Strategy
+ * ─────────
+ * SliderInput is an interactive component that drives a raw-mode TTY loop.
+ * We cannot run the full reactive loop in unit tests, so we test the
+ * behaviours that are accessible without a terminal:
+ *
+ *   • Fluent configuration (chaining returns $this, values are stored)
+ *   • resolve() returns the correct type and respects integer mode
+ *   • The rendered output contains the expected text elements
+ *
+ * render() writes directly to stdout, so we wrap those calls in
+ * ob_start() / ob_get_clean() and strip ANSI before asserting.
+ */
+#[CoversClass(SliderInput::class)]
+final class SliderInputTest extends TestCase
+{
+    protected function setUp(): void
+    {
+        Colors::enable();
+    }
+
+    protected function tearDown(): void
+    {
+        Colors::enable();
+    }
+
+    // ---------------------------------------------------------------
+    // Construction & fluent API
+    // ---------------------------------------------------------------
+
+    public function test_fluent_methods_return_self(): void
+    {
+        $slider = new SliderInput('Volume', 0, 100);
+
+        $this->assertSame($slider, $slider->min(0));
+        $this->assertSame($slider, $slider->max(100));
+        $this->assertSame($slider, $slider->step(5));
+        $this->assertSame($slider, $slider->default(50));
+        $this->assertSame($slider, $slider->integer());
+        $this->assertSame($slider, $slider->width(40));
+    }
+
+    // ---------------------------------------------------------------
+    // resolve() — float mode (default)
+    // ---------------------------------------------------------------
+
+    public function test_resolve_returns_float_by_default(): void
+    {
+        $slider = new SliderInput('Rate', 0.0, 1.0);
+        $slider->step(0.1)->default(0.5);
+
+        // Mount the component so state is initialised (setup() wires bindings)
+        $this->mountWithoutLoop($slider);
+
+        $result = $this->callResolve($slider);
+
+        $this->assertIsFloat($result);
+        $this->assertEqualsWithDelta(0.5, $result, 0.001);
+    }
+
+    // ---------------------------------------------------------------
+    // resolve() — integer mode
+    // ---------------------------------------------------------------
+
+    public function test_resolve_returns_int_in_integer_mode(): void
+    {
+        $slider = new SliderInput('Port', 1000, 9999);
+        $slider->step(1)->default(8080)->integer();
+
+        $this->mountWithoutLoop($slider);
+
+        $result = $this->callResolve($slider);
+
+        $this->assertIsInt($result);
+        $this->assertSame(8080, $result);
+    }
+
+    // ---------------------------------------------------------------
+    // resolve() — clamps to min / max
+    // ---------------------------------------------------------------
+
+    public function test_resolve_clamps_value_within_range(): void
+    {
+        $slider = new SliderInput('Speed', 0, 10);
+        $slider->step(1)->default(5);
+
+        $this->mountWithoutLoop($slider);
+
+        $result = $this->callResolve($slider);
+
+        $this->assertGreaterThanOrEqual(0, $result);
+        $this->assertLessThanOrEqual(10, $result);
+    }
+
+    // ---------------------------------------------------------------
+    // resolve() — snap to step
+    // ---------------------------------------------------------------
+
+    public function test_resolve_snaps_float_value_to_nearest_step(): void
+    {
+        // step = 0.25; default = 0.3 → nearest is 0.25
+        $slider = new SliderInput('Alpha', 0.0, 1.0);
+        $slider->step(0.25)->default(0.3);
+
+        $this->mountWithoutLoop($slider);
+
+        $result = $this->callResolve($slider);
+
+        $this->assertEqualsWithDelta(0.25, $result, 0.001);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — question appears in output
+    // ---------------------------------------------------------------
+
+    public function test_render_contains_question_text(): void
+    {
+        $slider = new SliderInput('Master volume', 0, 100);
+        $slider->step(1)->default(50);
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('Master volume', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — current value appears in output
+    // ---------------------------------------------------------------
+
+    public function test_render_shows_current_value(): void
+    {
+        $slider = new SliderInput('Brightness', 0, 100);
+        $slider->step(1)->default(75)->integer();
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('75', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — bar characters present
+    // ---------------------------------------------------------------
+
+    public function test_render_contains_bar_brackets(): void
+    {
+        $slider = new SliderInput('Level', 0, 10);
+        $slider->step(1)->default(5);
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('[', $output);
+        $this->assertStringContainsString(']', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — range hints (min and max values)
+    // ---------------------------------------------------------------
+
+    public function test_render_shows_min_and_max_hints(): void
+    {
+        $slider = new SliderInput('Timeout', 1, 60);
+        $slider->step(1)->default(30)->integer();
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('1', $output);
+        $this->assertStringContainsString('60', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — help text
+    // ---------------------------------------------------------------
+
+    public function test_render_contains_keyboard_hint(): void
+    {
+        $slider = new SliderInput('Value', 0, 100);
+        $slider->step(1)->default(50);
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('ENTER', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — ANSI disabled → plain output
+    // ---------------------------------------------------------------
+
+    public function test_render_works_with_colors_disabled(): void
+    {
+        Colors::disable();
+        $slider = new SliderInput('Gain', 0, 10);
+        $slider->step(1)->default(5);
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        // No ANSI escape sequences should appear
+        $this->assertStringContainsString('Gain', $output);
+        $this->assertStringContainsString('5', $output);
+        $this->assertStringContainsString('[', $output);
+        $this->assertStringContainsString(']', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // render() — thumb marker present (●)
+    // ---------------------------------------------------------------
+
+    public function test_render_contains_thumb_marker(): void
+    {
+        $slider = new SliderInput('Pan', -50, 50);
+        $slider->step(1)->default(0)->integer();
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        // The slider thumb is rendered as ●
+        $this->assertStringContainsString('●', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // Decimal formatting mirrors step precision
+    // ---------------------------------------------------------------
+
+    public function test_render_formats_value_with_correct_decimal_places(): void
+    {
+        $slider = new SliderInput('Rate', 0.0, 1.0);
+        $slider->step(0.01)->default(0.75);
+        $this->mountWithoutLoop($slider);
+
+        $output = $this->capture(static fn() => $slider->render());
+
+        $this->assertStringContainsString('0.75', $output);
+    }
+
+    // ---------------------------------------------------------------
+    // Helpers
+    // ---------------------------------------------------------------
+
+    /**
+     * Calls the protected setup() via mount() so state and bindings are ready,
+     * without launching the blocking run() loop.
+     */
+    private function mountWithoutLoop(SliderInput $slider): void
+    {
+        $ref = new \ReflectionObject($slider);
+        $method = $ref->getMethod('setup');
+        $method->setAccessible(true);
+        $method->invoke($slider);
+    }
+
+    /**
+     * Calls the protected resolve() via reflection.
+     */
+    private function callResolve(SliderInput $slider): mixed
+    {
+        $ref = new \ReflectionObject($slider);
+        $method = $ref->getMethod('resolve');
+        $method->setAccessible(true);
+
+        return $method->invoke($slider);
+    }
+
+    /**
+     * Captures stdout output from a callable and strips ANSI codes.
+     */
+    private function capture(callable $fn): string
+    {
+        ob_start();
+        $fn();
+
+        return Colors::strip((string) ob_get_clean());
+    }
+}