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https://sciencedirect.com

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
89
GRADE
B
FIX
1
REVIEW
4
PASS
10
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
52
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
95
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
82
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

4.63 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

5.13 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

654 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.053

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

4.63 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

6.67 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
17
10 PASS 4 REVIEW 1 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.1 MiB of 1.1 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
B
Page Weight Budget
1.1 MB transferred, 30 requests
REVIEW
1.1 MB transferred, 30 requests
Info::
Page weighs 1.8 MB (1.1 MB transferred)
Info::
30 HTTP requests
Info::
Estimated 0.23 g CO2 per page load
1.1 MB / 2.4 MB budget
1.1 MB transferred
30 requests
0.23 g CO2 per page load
HTML 613.1 KiB 55%
Other 316.2 KiB 28%
JavaScript 88.0 KiB 8%
Fonts 67.7 KiB 6%
Images 34.1 KiB 3%
Other 1.7 KiB 0%
Other 666 B 0%
Other 74 B 0%
0 2.4 MB 4.9 MB
Under budget
B
Image Optimization
6 images, 0 KB saveable
REVIEW
6 images, 0 KB saveable
Info::
All images are well-optimized
6 images 34 KB
0 oversized -0 KB
4 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1501ms total JS execution
REVIEW
1501ms total JS execution
Warning::
https://www.sciencedirect.com/cdn-cgi/challenge-pl...: 1057ms CPU time
Info::
Unattributable: 227ms CPU time
Info::
https://www.sciencedirect.com/: 216ms CPU time
Warning::
Third-party scripts: 1501ms (100% of total)

Main Thread Breakdown

Script Evaluation 70% Other 16% Style & Layout 5% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=9ed4d17f6e3a04ae1057ms1015ms19ms3rd
Unattributable227ms5ms0ms3rd
https://www.sciencedirect.com/216ms29ms4ms3rd
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
2 fonts (68 KB)
PASS
2 fonts (68 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

68 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 4.6 s LCP 5.1 sdata:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 33.9 KiB — 15 ms — font-display: swapdata:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 33.8 KiB — 17 ms — font-display: swap
octet-stream;base64,d09... unknown swap
Size 34 KB
Load time 15 ms
Start 204 ms
Risk FOUT — text flashes from fallback to web font
octet-stream;base64,d09... unknown swap
Size 34 KB
Load time 17 ms
Start 205 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~20 KB and ~40 ms

A+
JS Bundles
11 scripts, 0 KB unused
PASS
11 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=9ed4d17f6e3a04ae71 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/g/b0a7532ac8ec/api.js?onload=cFyL2&render=explicit17 KB—✓3rd
blob:https://www.sciencedirect.com/a30147dd-1c6d-40d9-a422-3449ec58d1190 KB—✓3rd
blob:https://www.sciencedirect.com/c8c8b775-5e0e-4967-8cdf-737fa9040226-0 KB—✓3rd
blob:https://challenges.cloudflare.com/52656928-eb80-4d3f-a2ce-24db5eef06780 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a-0 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a-0 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a0 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a0 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a-0 KB—✓3rd
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
1 hints, 0 missing preconnects
PASS
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)

Current Resource Hints

preconnect
—
preload
1
dns-prefetch
—
prefetch
—

1 resource hints configured

A
Page Weight Inventory
30 resources · 1.1 MB · 0 KB savings available
PASS
30 resources · 1.1 MB · 0 KB savings available
Warning::
Page weight 98 KB over 1MB target
Got: 1.1 MB Expected: ≤ 1 MB
Warning::
28 third-party resources (100% of weight)
Info::
2 resources over 200KB
30 resources · 1.1 MiB · 28 third-party 97.5 KiB over 1MB target
Document 55% · 613.7 KiB
Other 28% · 318.0 KiB
JavaScript 8% · 88.0 KiB
Font 6% · 67.7 KiB
Image 3% · 34.1 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A
HTTP Caching
max-age=3600 (1 hour)
PASS
max-age=3600 (1 hour)
Info::
Cache-Control header is set
Got: max-age=3600
Info::
Effective TTL: 1 hour (max-age=3600)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=3600

DirectiveValueMeaning
max-age3600Cache for 1 hour
Effective TTL: 3600 seconds
Network Waterfall
30 requests over 2697ms
INFO
0 ms 1.0 s 2.0 s 3.0 s 4.0 s 5.0 s FCP 4.6 s LCP 5.1 shttps://sciencedirect.com// https://sciencedirect.com/ — 301 — 599 B — 30 ms — h2https://www.sciencedirect.com/www.sciencedirect.com/ https://www.sciencedirect.com/ — 307 — 67 B — 89 ms — http/1.1https://sciencedirect.com// https://sciencedirect.com/ — 301 — 0 B — 1 ms — h2https://www.sciencedirect.com/www.sciencedirect.com/ https://www.sciencedirect.com/ — 403 — 518.9 KiB — 28 ms — h2https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/24/images/elsevier-non-solus-new-grey.svgsdfestaticassets-us-east-1.scienced... https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/24/images/elsevier-non-solus-new-grey.svg — -1 — 0 B — 196 ms — data:image/svg+xml;base64,PHN2ZwogICAgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIgogICAgdmVyc2lvb…data:image/svg+xml;base64,PHN2ZwogI... data:image/svg+xml;base64,PHN2ZwogICAgeG1sbnM9Imh0dHA6Ly93d3cudzMub3JnLzIwMDAvc3ZnIgogICAgdmVyc2lvb… — 200 — 0 B — 1 ms — datahttps://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=9ed4d17f6e3a04aewww.sciencedirect.com/cdn-cgi/chall... https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=9ed4d17f6e3a04ae — 200 — 70.7 KiB — 27 ms — h2https://www.sciencedirect.com/craft/hosnb?tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&rh=d3d3LnNjaWVuY2VkaXJlY3QuY29twww.sciencedirect.com/craft/hosnb?t... https://www.sciencedirect.com/craft/hosnb?tsoh=d3d3LnNjaWVuY2VkaXJlY3QuY29t&rh=d3d3LnNjaWVuY2VkaXJlY3QuY29t — 404 — 74 B — 9 ms — h2data:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…data:binary/octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIegABEAAAABpYAAAIc7AAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 200 — 33.9 KiB — 15 ms — datadata:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo…data:binary/octet-stream;base64,d09... data:binary/octet-stream;base64,d09GMgABAAAAAIdEABEAAAABpRgAAIbiAAEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGjo… — 200 — 33.8 KiB — 17 ms — datadata:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIGhlaWdodD0iNjQiIHZpZ…data:image/svg+xml;base64,PHN2ZyB4b... data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIGhlaWdodD0iNjQiIHZpZ… — 200 — 28.2 KiB — 9 ms — datadata:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI5MyIgaGVpZ…data:image/svg+xml;base64,PHN2ZyB4b... data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI5MyIgaGVpZ… — 200 — 1.5 KiB — 11 ms — datahttps://challenges.cloudflare.com/turnstile/v0/g/b0a7532ac8ec/api.js?onload=cFyL2&render=explicitchallenges.cloudflare.com/turnstile... https://challenges.cloudflare.com/turnstile/v0/g/b0a7532ac8ec/api.js?onload=cFyL2&render=explicit — 200 — 17.3 KiB — 101 ms — h2blob:https://www.sciencedirect.com/a30147dd-1c6d-40d9-a422-3449ec58d119www.sciencedirect.com/a30147dd-1c6d... blob:https://www.sciencedirect.com/a30147dd-1c6d-40d9-a422-3449ec58d119 — -1 — 0 B — 0 ms — https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/103/images/favSD.icosdfestaticassets-eu-west-1.scienced... https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/103/images/favSD.ico — -1 — 0 B — 70 ms — https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/flow/ov1/1233245715:1776356029:PQ6m1bkyl1RD8sI8NMU8NdiDqVLoyqaUBySDmO8pfoY/9ed4d17f6e3a04ae/M9FkVzixgjMNw2ZokTQ_avsqepN97mZCvDatbG87oTE-1776359582-1.2.1.1-_WGo54eHV8gwcOrmrvQTJr18yu4D_4TH.XEP1XmJYLMdETsGYoeI9mO9uVxY1nLAwww.sciencedirect.com/cdn-cgi/chall... https://www.sciencedirect.com/cdn-cgi/challenge-platform/h/g/flow/ov1/1233245715:1776356029:PQ6m1bkyl1RD8sI8NMU8NdiDqVLoyqaUBySDmO8pfoY/9ed4d17f6e3a04ae/M9FkVzixgjMNw2ZokTQ_avsqepN97mZCvDatbG87oTE-1776359582-1.2.1.1-_WGo54eHV8gwcOrmrvQTJr18yu4D_4TH.XEP1XmJYLMdETsGYoeI9mO9uVxY1nLA — 200 — 13.4 KiB — 31 ms — h2blob:https://www.sciencedirect.com/c8c8b775-5e0e-4967-8cdf-737fa9040226www.sciencedirect.com/c8c8b775-5e0e... blob:https://www.sciencedirect.com/c8c8b775-5e0e-4967-8cdf-737fa9040226 — 200 — -1 B — 27 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/turnstile/f/ov2/av0/rch/4a264/0x4AAAAAAAAjq6WYeRDKmebM/light/fbE/new/normal?lang=autochallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/turnstile/f/ov2/av0/rch/4a264/0x4AAAAAAAAjq6WYeRDKmebM/light/fbE/new/normal?lang=auto — 200 — 94.2 KiB — 105 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/cmg/1challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/cmg/1 — 200 — 208 B — 22 ms — h3blob:https://challenges.cloudflare.com/52656928-eb80-4d3f-a2ce-24db5eef0678challenges.cloudflare.com/52656928-... blob:https://challenges.cloudflare.com/52656928-eb80-4d3f-a2ce-24db5eef0678 — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/flow/ov1/3520730589:1776356030:eN2sgrD-zofR7dpB1mBZXyTQDCBFwk1Uf5ETspx84aU/9ed4d181d80200bd/_5Khs6cnykFg88MZGdrMFOtEnGu_15AhYUZjdD.4Fsw-1776359583-1.2.1.1-fVlLVU21DhZIxEPgAuqYbkeZ3IzH0gmszGHP9rT_AcjKG3F0._VYDsO7nAg79sQ5challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/flow/ov1/3520730589:1776356030:eN2sgrD-zofR7dpB1mBZXyTQDCBFwk1Uf5ETspx84aU/9ed4d181d80200bd/_5Khs6cnykFg88MZGdrMFOtEnGu_15AhYUZjdD.4Fsw-1776359583-1.2.1.1-fVlLVU21DhZIxEPgAuqYbkeZ3IzH0gmszGHP9rT_AcjKG3F0._VYDsO7nAg79sQ5 — 200 — 280.0 KiB — 181 ms — h3blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3achallenges.cloudflare.com/9e0b9312-... blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a — 200 — -1 B — 20 ms — blobblob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3achallenges.cloudflare.com/9e0b9312-... blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a — 200 — -1 B — 44 ms — blobblob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3achallenges.cloudflare.com/9e0b9312-... blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a — -1 — 0 B — 0 ms — blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3achallenges.cloudflare.com/9e0b9312-... blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/pat/9ed4d181d80200bd/1776359583337/7663299cf54e54e02c2d53b7f523f9526642389bd74c8ad59d3d59009076c0b4/UD7kR8dGuj5mp8Jchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/pat/9ed4d181d80200bd/1776359583337/7663299cf54e54e02c2d53b7f523f9526642389bd74c8ad59d3d59009076c0b4/UD7kR8dGuj5mp8J — 401 — 1.7 KiB — 23 ms — h3blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3achallenges.cloudflare.com/9e0b9312-... blob:https://challenges.cloudflare.com/9e0b9312-bb62-49d0-b3ec-a7052de5dc3a — 200 — -1 B — 13 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/d/9ed4d181d80200bd/1776359583339/ao0HwO3W3dV1XPPchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/d/9ed4d181d80200bd/1776359583339/ao0HwO3W3dV1XPP — 200 — 4.3 KiB — 22 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/flow/ov1/3520730589:1776356030:eN2sgrD-zofR7dpB1mBZXyTQDCBFwk1Uf5ETspx84aU/9ed4d181d80200bd/_5Khs6cnykFg88MZGdrMFOtEnGu_15AhYUZjdD.4Fsw-1776359583-1.2.1.1-fVlLVU21DhZIxEPgAuqYbkeZ3IzH0gmszGHP9rT_AcjKG3F0._VYDsO7nAg79sQ5challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/g/flow/ov1/3520730589:1776356030:eN2sgrD-zofR7dpB1mBZXyTQDCBFwk1Uf5ETspx84aU/9ed4d181d80200bd/_5Khs6cnykFg88MZGdrMFOtEnGu_15AhYUZjdD.4Fsw-1776359583-1.2.1.1-fVlLVU21DhZIxEPgAuqYbkeZ3IzH0gmszGHP9rT_AcjKG3F0._VYDsO7nAg79sQ5 — 200 — 22.8 KiB — 56 ms — h3blob:https://challenges.cloudflare.com/9c37078c-4314-4185-9a4f-29c923e1aff6challenges.cloudflare.com/9c37078c-... blob:https://challenges.cloudflare.com/9c37078c-4314-4185-9a4f-29c923e1aff6 — 200 — -1 B — 15 ms — blob
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 1501ms · 590KB · $20/mo
www.sciencedirect.com
Other
Costly
Execution 1057ms
Transfer 71 KB
Monthly Cost $14/mo
Unattributable
Other
Costly
Execution 227ms
Transfer 0 KB
Monthly Cost $3/mo
www.sciencedirect.com
Other
Costly
Execution 216ms
Transfer 519 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • www.sciencedirect.com adds 1057ms and costs ~$14/month
  • Unattributable adds 227ms and costs ~$3/month
  • www.sciencedirect.com adds 216ms and costs ~$3/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.sciencedirect.com takes 1057ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

Unattributable takes 227ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.sciencedirect.com takes 216ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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