diff --git a/src/components/OnboardingTour.tsx b/src/components/OnboardingTour.tsx
index 4a9fa0e6..d5c163bc 100644
--- a/src/components/OnboardingTour.tsx
+++ b/src/components/OnboardingTour.tsx
@@ -251,7 +251,7 @@ export default function OnboardingTour() {
   useEffect(() => {
   if (localStorage.getItem(TOUR_KEY)) return;
   const t = setTimeout(async () => {
-    const rect = await measureTarget(TOUR_STEPS[0].targetId);
+    const rect = await measureTarget(TOUR_STEPS[0]?.targetId ?? "");
     if (rect) {
       setTargetRect(rect);
       setVisible(true);
@@ -267,7 +267,7 @@ useEffect(() => {
     isFirstRender.current = false;
     return;
   }
-  measureTarget(TOUR_STEPS[stepIndex].targetId).then((rect) => {
+  measureTarget(TOUR_STEPS[stepIndex]?.targetId ?? "").then((rect) => {
     if (rect) {
       setTargetRect(rect);
       setTimeout(() => tooltipRef.current?.focus(), 50);
@@ -285,7 +285,7 @@ useEffect(() => {
   useEffect(() => {
   if (!visible) return;
   const onResize = () => {
-    measureTarget(TOUR_STEPS[stepIndex].targetId).then(setTargetRect);
+    measureTarget(TOUR_STEPS[stepIndex]?.targetId ?? "").then(setTargetRect);
   };
   window.addEventListener("resize", onResize);
   return () => window.removeEventListener("resize", onResize);
@@ -318,7 +318,7 @@ useEffect(() => {
       />
       <Spotlight rect={targetRect} />
       <Tooltip
-        step={TOUR_STEPS[stepIndex]}
+        step={TOUR_STEPS[stepIndex]!}
         stepIndex={stepIndex}
         totalSteps={TOUR_STEPS.length}
         rect={targetRect}
diff --git a/src/components/PresetSelector.tsx b/src/components/PresetSelector.tsx
index 817c8d06..5ec5bd7c 100644
--- a/src/components/PresetSelector.tsx
+++ b/src/components/PresetSelector.tsx
@@ -56,7 +56,7 @@ const QUICK_ACTIONS = [
     platform: "Instagram",
     icon: (
       <svg viewBox="0 0 24 24" fill="currentColor" className="w-5 h-5">
-        <path d="M12 2.163c3.204 0 3.584.012 4.85.07 3.252.148 4.771 1.691 4.919 4.919.058 1.265.069 1.645.069 4.849 0 3.205-.012 3.584-.069 4.849-.149 3.225-1.664 4.771-4.919 4.919-1.266.058-1.644.07-4.85.07-3.204 0-3.584-.012-4.849-.07-3.26-.149-4.771-1.699-4.919-4.92-.058-1.265-.07-1.644-.07-4.849 0-3.204.013-3.583.07-4.849.149-3.227 1.664-4.771 4.919-4.919 1.266-.057 1.645-.069 4.849-.069zM12 0C8.741 0 8.333.014 7.053.072 2.695.272.273 2.69.073 7.052.014 8.333 0 8.741 0 12c0 3.259.014 3.668.072 4.948.2 4.358 2.618 6.78 6.98 6.98C8.333 23.986 8.741 24 12 24c3.259 0 3.668-.014 4.948-.072 4.354-.2 6.782-2.618 6.979-6.98.059-1.28.073-1.689.073-4.948 0-3.259-.014-3.667-.072-4.947-.196-4.354-2.617-6.78-6.979-6.98C15.668.014 15.259 0 12 0zm0 5.838a6.162 6.162 0 100 12.324 6.162 6.162 0 000-12.324zM12 16a4 4 0 110-8 4 4 0 010 8zm6.406-11.845a1.44 1.44 0 100 2.881 1.44 1.44 0 000-2.881z"/>
+        <path d="M12 2.163c3.204 0 3.584.012 4.85.07 3.252.148 4.771 1.691 4.919 4.919.058 1.265.069 1.645.069 4.849 0 3.205-.012 3.584-.069 4.849-.149 3.225-1.664 4.771-4.919 4.919-1.266.058-1.644.07-4.85.07-3.204 0-3.584-.012-4.849-.07-3.26-.149-4.771-1.699-4.919-4.92-.058-1.265-.07-1.644-.07-4.849 0-3.204.013-3.583.07-4.849.149-3.227 1.664-4.771 4.919-4.919 1.266-.057 1.645-.069 4.849-.069zM12 0C8.741 0 8.333.014 7.053.072 2.695.272.273 2.69.073 7.052.014 8.333 0 8.741 0 12c0 3.259.014 3.668.072 4.948.2 4.358 2.618 6.78 6.98 6.98C8.333 23.986 8.741 24 12 24c3.259 0 3.668-.014 4.948-.072 4.354-.2 6.782-2.618 6.979-6.98.059-1.28.073-1.689.073-4.948 0-3.259-.014-3.667-.072-4.947-.196-4.354-2.617-6.78-6.979-6.98C15.668.014 15.259 0 12 0zm0 5.838a6.162 6.162 0 100 12.324 6.162 6.162 0 000-12.324zM12 16a4 4 0 110-8 4 4 0 010 8zm6.406-11.845a1.44 1.44 0 100 2.881 1.44 1.44 0 000-2.881z" />
       </svg>
     ),
   },
@@ -66,7 +66,7 @@ const QUICK_ACTIONS = [
     platform: "TikTok",
     icon: (
       <svg viewBox="0 0 24 24" fill="currentColor" className="w-5 h-5">
-        <path d="M19.59 6.69a4.83 4.83 0 01-3.77-4.25V2h-3.45v13.67a2.89 2.89 0 01-2.88 2.5 2.89 2.89 0 01-2.89-2.89 2.89 2.89 0 012.89-2.89c.28 0 .54.04.79.1V9.01a6.32 6.32 0 00-.79-.05 6.34 6.34 0 00-6.34 6.34 6.34 6.34 0 006.34 6.34 6.34 6.34 0 006.33-6.34V8.69a8.18 8.18 0 004.78 1.52V6.75a4.85 4.85 0 01-1.01-.06z"/>
+        <path d="M19.59 6.69a4.83 4.83 0 01-3.77-4.25V2h-3.45v13.67a2.89 2.89 0 01-2.88 2.5 2.89 2.89 0 01-2.89-2.89 2.89 2.89 0 012.89-2.89c.28 0 .54.04.79.1V9.01a6.32 6.32 0 00-.79-.05 6.34 6.34 0 00-6.34 6.34 6.34 6.34 0 006.34 6.34 6.34 6.34 0 006.33-6.34V8.69a8.18 8.18 0 004.78 1.52V6.75a4.85 4.85 0 01-1.01-.06z" />
       </svg>
     ),
   },
@@ -76,7 +76,7 @@ const QUICK_ACTIONS = [
     platform: "YouTube",
     icon: (
       <svg viewBox="0 0 24 24" fill="currentColor" className="w-5 h-5">
-        <path d="M23.498 6.186a3.016 3.016 0 00-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 00.502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 002.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 002.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z"/>
+        <path d="M23.498 6.186a3.016 3.016 0 00-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 00.502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 002.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 002.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z" />
       </svg>
     ),
   },
@@ -86,7 +86,7 @@ const QUICK_ACTIONS = [
     platform: "YouTube",
     icon: (
       <svg viewBox="0 0 24 24" fill="currentColor" className="w-5 h-5">
-        <path d="M23.498 6.186a3.016 3.016 0 00-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 00.502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 002.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 002.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z"/>
+        <path d="M23.498 6.186a3.016 3.016 0 00-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 00.502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 002.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 002.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z" />
       </svg>
     ),
   },
@@ -96,7 +96,7 @@ const QUICK_ACTIONS = [
     platform: "Twitter",
     icon: (
       <svg viewBox="0 0 24 24" fill="currentColor" className="w-5 h-5">
-        <path d="M18.244 2.25h3.308l-7.227 8.26 8.502 11.24H16.17l-4.714-6.231-5.401 6.231H2.746l7.73-8.835L1.254 2.25H8.08l4.259 5.63L18.244 2.25zm-1.161 17.52h1.833L7.084 4.126H5.117L17.083 19.77z"/>
+        <path d="M18.244 2.25h3.308l-7.227 8.26 8.502 11.24H16.17l-4.714-6.231-5.401 6.231H2.746l7.73-8.835L1.254 2.25H8.08l4.259 5.63L18.244 2.25zm-1.161 17.52h1.833L7.084 4.126H5.117L17.083 19.77z" />
       </svg>
     ),
   },
@@ -122,14 +122,18 @@ export default function PresetSelector({ recipe, onChange }: Props) {
 
   const handleWidthChange = useCallback(
     (width: number) => {
-      onChange({ customWidth: width });
+      if (!isNaN(width) && width >= 16 && width <= 7680) {
+        onChange({ customWidth: width });
+      }
     },
     [onChange],
   );
 
   const handleHeightChange = useCallback(
     (height: number) => {
-      onChange({ customHeight: height });
+      if (!isNaN(height) && height >= 16 && height <= 7680) {
+        onChange({ customHeight: height });
+      }
     },
     [onChange],
   );
@@ -280,6 +284,7 @@ export default function PresetSelector({ recipe, onChange }: Props) {
             <input
               id="custom-width"
               type="number"
+              autoComplete="off" 
               min={16}
               max={7680}
               step={2}
@@ -305,6 +310,7 @@ export default function PresetSelector({ recipe, onChange }: Props) {
             <input
               id="custom-height"
               type="number"
+              autoComplete="off"
               min={16}
               max={7680}
               step={2}
diff --git a/src/components/ThumbnailStrip.tsx b/src/components/ThumbnailStrip.tsx
index c4a186ef..54d57db0 100644
--- a/src/components/ThumbnailStrip.tsx
+++ b/src/components/ThumbnailStrip.tsx
@@ -70,7 +70,7 @@ export default function ThumbnailStrip({
     for (let t = 0; t <= duration; t += intervalSeconds) {
       times.push(Math.min(t, duration - 0.1));
     }
-    if (times[times.length - 1] < duration - 0.5) {
+    if ((times[times.length - 1] ?? 0) < duration - 0.5) {
       times.push(duration - 0.1);
     }
 
@@ -79,7 +79,7 @@ export default function ThumbnailStrip({
     for (let i = 0; i < times.length; i++) {
       if (abortRef.current) break;
 
-      const time = times[i];
+      const time = times[i] ?? 0;
       await new Promise<void>((resolve) => {
         const onSeeked = () => {
           video.removeEventListener("seeked", onSeeked);
@@ -117,7 +117,7 @@ export default function ThumbnailStrip({
   const activeIndex = thumbnails.findIndex(
     (t, i) =>
       currentTime >= t.time &&
-      (i === thumbnails.length - 1 || currentTime < thumbnails[i + 1].time)
+      (i === thumbnails.length - 1 || currentTime < (thumbnails[i + 1]?.time ?? Infinity))
   );
 
   if (!videoSrc) return null;
diff --git a/src/components/TipCarousel.tsx b/src/components/TipCarousel.tsx
index 0500dd19..c16fde92 100644
--- a/src/components/TipCarousel.tsx
+++ b/src/components/TipCarousel.tsx
@@ -80,7 +80,8 @@ export default function TipCarousel() {
   };
 
   const activeTip = TIPS[activeIdx];
-  const IconComponent = activeTip.icon;
+  if (!activeTip) return null;
+  const IconComponent = activeTip.icon; 
 
   return (
     <div 
diff --git a/src/components/VideoEditor.tsx b/src/components/VideoEditor.tsx
index 6e297539..ec2eabc1 100644
--- a/src/components/VideoEditor.tsx
+++ b/src/components/VideoEditor.tsx
@@ -401,7 +401,7 @@ export default function VideoEditor() {
                 {recommendedPreset && (
                   <div className="mb-4 rounded-2xl border border-film-200 bg-film-50 p-3 text-sm text-film-700">
                     <p>
-                      We detected a {recommendedPreset.label.replace(/\s/g, "")} video → Recommended: {recommendedPreset.platform.split("·")[0].trim()} ({recommendedPreset.label.replace(/\s/g, "")})
+                      We detected a {recommendedPreset.label.replace(/\s/g, "")} video → Recommended: {(recommendedPreset.platform.split("·")[0] ?? "").trim()} ({recommendedPreset.label.replace(/\s/g, "")})
                     </p>
                   </div>
                 )}
diff --git a/src/components/WaveformCanvas.tsx b/src/components/WaveformCanvas.tsx
index a170a0e7..cff6a6bc 100644
--- a/src/components/WaveformCanvas.tsx
+++ b/src/components/WaveformCanvas.tsx
@@ -54,7 +54,7 @@ export default function WaveformCanvas({ samples, loading, hasAudio }: Props) {
     ctx.globalAlpha = 0.7;
 
     for (let i = 0; i < samples.length; i++) {
-      const amplitude = samples[i];
+      const amplitude = samples[i] ?? 0;
       const barHeight = Math.max(amplitude * (height * 0.92), 1.5);
       const x = i * barWidth;
       const y = midY - barHeight / 2;
diff --git a/tsconfig.json b/tsconfig.json
index 5310d2e1..5fe25c1c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,6 +5,7 @@
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
+    "noUncheckedIndexedAccess": true,
     "noEmit": true,
     "esModuleInterop": true,
     "module": "esnext",