Chart Type for Time-Series Forecast. Keywords: forecast, prediction, confidence, band, projection, estimate. Best Chart: Line with Confidence Band. Secondary Options: Ribbon Chart. When to Use: Historical data + model predictions; communicating uncertainty range to non-technical stakeholders. When NOT to Use: No historical baseline; prediction confidence is too low to be useful; audience is not data-literate. Data Volume Threshold: Keep historical window to 30–90 days for readability; forecast horizon ≤ 30% of visible x-axis range. Color Guidance: Actual: solid line #0080FF. Forecast: dashed #FF9500. Confidence band: 15% opacity fill same hue. Accessibility: AA — Toggle between actual-only and forecast views. Legend must distinguish lines beyond color (solid vs dashed).. A11y Fallback: Toggle actual/forecast independently; legend labels must include line-style description. Library: Chart.js, ApexCharts, Plotly. Interactive Level: Hover + Toggle.