theme.shadow without border dark

theme.shadow-without-border-dark

Rule ID: theme.shadow-without-border-dark Severity: WARN Category: theme Target Standards: Material Design 3 Elevation Guidelines, W3C DTCG Elevation & Shadow Tokens, Dark Mode Optical Physics & Surface Boundaries

---

1. Overview & Core Invariant

Detects elevated containers with shadow lacking border or ring indicators in dark mode

Core Invariant:

"Elevated containers in dark mode must include a border or ring to maintain boundary perception against dark canvas backgrounds."

---

2. Technical Grounding & Engine Realities

In dark mode, standard drop shadows (e.g. shadow-md, shadow-lg, shadow-xl) vanish because black alpha shadows cannot produce luminance contrast against dark or black canvases (optical shadow collapse):

1. Boundary Disappearance: High-elevation dialogs, popovers, and cards visually merge into the background canvas.
2. Loss of Spatial Hierarchy: Users lose depth perception and cannot distinguish foreground cards from background sections.
3. Inconsistent Multi-Theme UX: Interfaces that look well-separated in light mode become an unsegmented flat surface in dark mode.

Charites enforces pairing elevated shadows with subtle boundary tokens (e.g. border border-border or ring-1 ring-border).

---

3. Vulnerability & Risk Taxonomy

Risk Vector	Severity	Impact
Dark Mode Shadow Collapse	MEDIUM	Elevated elements blend completely into background surfaces in dark themes, eliminating depth cues.
Spatial Hierarchy Degradation	MEDIUM	Users experience layout confusion between distinct interactive surfaces and parent containers.

---

4. Non-Compliant Code Patterns (Bad Examples)

TSX (Elevated card using shadow-xl without border boundary):

<div className="bg-card shadow-xl rounded-xl p-6">Modal Dialog</div>

ASTRO (High-elevation floating panel without border or ring):

<div class="shadow-lg rounded-2xl bg-zinc-900 p-4">Floating Panel</div>

---

5. Compliant Implementation Patterns (Good Examples)

TSX (Elevated card reinforced with border-border boundary):

<div className="bg-card border border-border shadow-xl rounded-xl p-6">Modal Dialog</div>

ASTRO (Elevated panel reinforced with ring token):

<div class="shadow-lg ring-1 ring-border rounded-2xl bg-zinc-900 p-4">Floating Panel</div>

---

6. Detection & Verification Pipeline (How The Rule Evaluates Code)

This theme rule evaluates source templates against the project's design token graph:

flowchart TD
    Node["AST Node (Astro / TSX element)"] --> Extract["1. Extract Class Names (e.g. 'hover:bg-primary/10')"]
    Extract --> Strip["2. Strip Variants (hover:, dark:, sm:) -> 'bg-primary/10'"]
    Strip --> Split["3. Split Opacity Modifier -> Utility: 'bg-primary', Opacity: '/10'"]
    Split --> Convention["4. Query TokenConvention (Candidate: '--color-primary-light')"]
    Convention --> GraphQuery{"5. Check Token Graph (Does token exist in active scope?)"}
    GraphQuery -- "No (Banana Test)" --> Safe["Pass (Valid Custom / Untokenized Color)"]
    GraphQuery -- "Yes (Official Token Exists)" --> IgnoreCheck{"6. Check charites:ignore directive"}
    IgnoreCheck -- "Ignored" --> Safe
    IgnoreCheck -- "Not Ignored" --> Diag["7. Emit Diagnostic: theme.shadow-without-border-dark with Replacement Suggestion"]

Loading

Step-by-Step Evaluation:

1. AST Node Traversal: internal/analyzer streams JSX/Astro AST elements to the rule's Evaluate visitor.
2. Variant Normalization: Strips responsive (sm:, md:), interaction state (hover:, focus:), and theme (dark:) prefixes to isolate the core utility class.
3. Modifier Extraction: Parses utility segments and extracts slash opacity modifiers.
4. Token Convention Resolution: Consults the TokenConvention adapter to determine the official semantic design token replacement candidate.
5. Token Graph Verification (Banana Test): Queries token.Context to verify that the candidate token is declared in global.css or tokens.json within the element's scope. If not declared, the custom value is permitted without a false-positive diagnostic.
6. Directive Suppression Check: Inspects preceding AST comments for charites:ignore theme.shadow-without-border-dark.
7. Diagnostic Emission: Produces a structured diagnostic with line number, column span, and actionable replacement suggestion.

---

7. Verification & Test Harness (How The Test Works: 1-SSOT Tri-Corpus)

This rule is rigorously tested and validated across the canonical 1-SSOT Tri-Corpus in tests/correctness/theme.shadow-without-border-dark/:

flowchart TD
    subgraph GoldenCorpus ["1-SSOT Tri-Corpus Test Matrix for theme.shadow-without-border-dark"]
        subgraph P ["Positive Corpus (tests/correctness/theme.shadow-without-border-dark/positive/)"]
            P1["P1: Obvious Direct Violation"]
            P2["P2: Indirect / Variant Concatenation"]
            P3["P3: Helper / clsx / cn Wrapper"]
            P4["P4: Deeply Nested Elements"]
            P5["P5: Aliased Imports / Re-exports"]
        end
        subgraph N ["Negative Corpus (tests/correctness/theme.shadow-without-border-dark/negative/)"]
            N1["N1: Valid Design Tokens"]
            N2["N2: Explicit charites:ignore Directive"]
            N3["N3: Third-Party / Vendor Components"]
            N4["N4: Clean Semantic HTML"]
            N5["N5: Untokenized Custom Values (Banana Test)"]
        end
        subgraph A ["Adversarial Corpus (tests/correctness/theme.shadow-without-border-dark/adversarial/)"]
            A1["A1: Template Literal Interpolations"]
            A2["A2: Ternary Conditional Expressions"]
            A3["A3: Spread Properties & Dynamic Overrides"]
            A4["A4: Dynamic Object Class Syntax"]
            A5["A5: Shadowed Variable Identifiers"]
            A6["A6: Nested Closures & HOC Wrappers"]
            A7["A7: Obfuscated Classes & Cyclic Tokens"]
        end
    end

    P --> TestRunner["Automated Runner (rule_test.go)"]
    N --> TestRunner
    A --> TestRunner
    TestRunner --> Gates["Quality Gates: Zero Panic, Zero False-Positive, Zero Bypass"]

Loading

• Positive Fixtures (P1-P5): Verified to trigger diagnostics at exact lines and column spans.
• Negative Fixtures (N1-N5): Verified to produce zero diagnostics on valid tokens and legitimate exemptions.
• Adversarial Fixtures (A1-A7): Verified to prevent evasion across dynamic expressions, string interpolations, and cyclic references.

---

8. How to Suppress (Ignore Directives)

If this pattern is required for an intentional exception, suppress the diagnostic using the canonical Charites Rule ID:

<!-- charites:ignore theme.shadow-without-border-dark intentional exception -->

// charites:ignore theme.shadow-without-border-dark intentional exception

---

9. Configuration Reference (charites.yaml)

rules:
  theme.shadow-without-border-dark:
    severity: warn # error | warn | info | off