container-lines: Design & UI for AI Agents | OpenAgentSkill

Overview

Add vertical container-size guide lines with mini corner squares for precise, structured web layouts. Use when asked for container lines, measured layout guides, vertical boundary lines, editorial grid markers, or small corner-square frame details.

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Container Lines

Use When

A page needs subtle vertical guides that reveal the content container width.
A hero, section, or product page feels too loose and needs structural tension.
The design calls for mini corner squares, measured edges, or quiet technical framing.

Rules

Draw lines at the left and right edges of the main content container.
Keep lines thin: 1px with low opacity.
Add mini squares at container corners or section intersections.
Keep the line system consistent across sections; do not change width per section.
Place lines behind content but above the page background.
Disable pointer events so the guides never block UI.

Base Tokens

:root {
  --container-max: 1120px;
  --container-pad: clamp(20px, 4vw, 48px);
  --line-color: rgba(24, 24, 27, 0.14);
  --line-strong: rgba(24, 24, 27, 0.28);
  --corner-size: 6px;
}

Page Container Lines

Use pseudo-elements on the layout shell.

.container-lines {
  position: relative;
  isolation: isolate;
}

.container-lines::before,
.container-lines::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: -1;
  width: 1px;
  background: var(--line-color);
  pointer-events: none;
}

.container-lines::before {
  left: max(var(--container-pad), calc((100% - var(--container-max)) / 2));
}

.container-lines::after {
  right: max(var(--container-pad), calc((100% - var(--container-max)) / 2));
}

Corner Squares

Add four small squares to sections that need a precise measured feel.

.corner-squares {
  position: relative;
}

.corner-squares > .corner {
  position: absolute;
  width: var(--corner-size);
  height: var(--corner-size);
  background: var(--line-strong);
  pointer-events: none;
}

.corner.top-left { top: 0; left: 0; transform: translate(-50%, -50%); }
.corner.top-right { top: 0; right: 0; transform: translate(50%, -50%); }
.corner.bottom-left { bottom: 0; left: 0; transform: translate(-50%, 50%); }
.corner.bottom-right { right: 0; bottom: 0; transform: translate(50%, 50%); }

<main class="container-lines">
  <section class="corner-squares">
    <span class="corner top-left"></span>
    <span class="corner top-right"></span>
    <span class="corner bottom-left"></span>
    <span class="corner bottom-right"></span>
    ...
  </section>
</main>

Minimal Section Wrapper

Use the same container width as the line positions.

.content-container {
  width: min(100% - (var(--container-pad) * 2), var(--container-max));
  margin-inline: auto;
}

Taste Rules

Use lines as structure, not decoration. They should organize the page quietly.
Do not add lines to every nested component; keep them at page or major-section level.
Mini squares should be small and exact, usually 4px to 8px.
Avoid bright accent colors unless the entire visual system is technical or industrial.
Keep container max-width and padding shared between content and guide lines.

Quick Checks

The vertical lines align exactly with the content container edges.
Corner squares sit on real container or section corners, not arbitrary positions.
Lines remain subtle on light and dark backgrounds.
Mobile still has enough padding between the line and content.
Guides do not intercept clicks, hovers, or text selection.

View source ↗

File metadata

name: container-lines
description: Add vertical container-size guide lines with mini corner squares for precise, structured web layouts. Use when asked for container lines, measured layout guides, vertical boundary lines, editorial grid markers, or small corner-square frame details.

View original text

---
name: container-lines
description: Add vertical container-size guide lines with mini corner squares for precise, structured web layouts. Use when asked for container lines, measured layout guides, vertical boundary lines, editorial grid markers, or small corner-square frame details.
---

# Container Lines

## Use When
- A page needs subtle vertical guides that reveal the content container width.
- A hero, section, or product page feels too loose and needs structural tension.
- The design calls for mini corner squares, measured edges, or quiet technical framing.

## Rules
1. Draw lines at the left and right edges of the main content container.
2. Keep lines thin: `1px` with low opacity.
3. Add mini squares at container corners or section intersections.
4. Keep the line system consistent across sections; do not change width per section.
5. Place lines behind content but above the page background.
6. Disable pointer events so the guides never block UI.

## Base Tokens

```css
:root {
  --container-max: 1120px;
  --container-pad: clamp(20px, 4vw, 48px);
  --line-color: rgba(24, 24, 27, 0.14);
  --line-strong: rgba(24, 24, 27, 0.28);
  --corner-size: 6px;
}
```

## Page Container Lines
Use pseudo-elements on the layout shell.

```css
.container-lines {
  position: relative;
  isolation: isolate;
}

.container-lines::before,
.container-lines::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  z-index: -1;
  width: 1px;
  background: var(--line-color);
  pointer-events: none;
}

.container-lines::before {
  left: max(var(--container-pad), calc((100% - var(--container-max)) / 2));
}

.container-lines::after {
  right: max(var(--container-pad), calc((100% - var(--container-max)) / 2));
}
```

## Corner Squares
Add four small squares to sections that need a precise measured feel.

```css
.corner-squares {
  position: relative;
}

.corner-squares > .corner {
  position: absolute;
  width: var(--corner-size);
  height: var(--corner-size);
  background: var(--line-strong);
  pointer-events: none;
}

.corner.top-left { top: 0; left: 0; transform: translate(-50%, -50%); }
.corner.top-right { top: 0; right: 0; transform: translate(50%, -50%); }
.corner.bottom-left { bottom: 0; left: 0; transform: translate(-50%, 50%); }
.corner.bottom-right { right: 0; bottom: 0; transform: translate(50%, 50%); }
```

```html
<main class="container-lines">
  <section class="corner-squares">
    <span class="corner top-left"></span>
    <span class="corner top-right"></span>
    <span class="corner bottom-left"></span>
    <span class="corner bottom-right"></span>
    ...
  </section>
</main>
```

## Minimal Section Wrapper
Use the same container width as the line positions.

```css
.content-container {
  width: min(100% - (var(--container-pad) * 2), var(--container-max));
  margin-inline: auto;
}
```

## Taste Rules
- Use lines as structure, not decoration. They should organize the page quietly.
- Do not add lines to every nested component; keep them at page or major-section level.
- Mini squares should be small and exact, usually `4px` to `8px`.
- Avoid bright accent colors unless the entire visual system is technical or industrial.
- Keep container max-width and padding shared between content and guide lines.

## Quick Checks
- The vertical lines align exactly with the content container edges.
- Corner squares sit on real container or section corners, not arbitrary positions.
- Lines remain subtle on light and dark backgrounds.
- Mobile still has enough padding between the line and content.
- Guides do not intercept clicks, hovers, or text selection.

Review the source

Skill source recorded

Skill instructions are recorded. This is not a runtime test, safety guarantee or compatibility certification.

Review before install: Avoid automatic install

License: Apache-2.0

Dependency or permission surface needs review
Permission surface may require sandboxing
Quality score needs review
Permission surface needs review: secrets or environment access, shell or command execution
Stars/forks activity: 289 stars, 39 forks; issue activity unavailable in current metadata
Dependency/runtime risk: command execution surface, credential or environment access
Permission surface: secrets or environment access, shell or command execution

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Start with one small task

1Read the source. Confirm the input, expected output, dependencies and permissions.
2Ask your agent for a plan. Approve setup and any costs before running a small isolated test.
3Check the output and changed files. Report only what actually ran; keep the source revision for reproduction.

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Source & usage notes

Indexed

Repository metadata and review signals are advisory. Popularity, source discovery and successful execution are different facts.

Source repository: boraoztunc/skills
License: Apache-2.0
Version: 1.0.0
Last GitHub push: Aug 15, 2026
Registry updated: Sep 3, 2026
Instruction path: container-lines/SKILL.md @ 645553ca7622

Version reported in registry metadata; check source releases before relying on it.

Quality

71/100

Strong

Trust

65/100

Sandbox only

Agent access

This page exposes the same decision, trust, audit, use-case, and install signals through the Registry API, so agents can rank this skill without scraping the UI.

Open install API LLM text format Open manifest Auto-resolve Plan

More details

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}

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Creator: boraoztunc
Source: boraoztunc/skills
Indexed by: OpenAgentSkill community index

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