# Letters — Style Reference
> morning clinic under open sky — a sterile white desk beneath a wash of soft blue, dotted with surgical-blue instruments.
**Theme:** light
Source measurements are normalized; roles and recommendations are interpreted. Font summary lists are independent, not paired by position. HTML examples are reconstructions, not source components.
Letters is a medical letterwriting tool that opens with an open-sky gradient hero — a soft blue atmospheric band that sets a calm, clinical tone before dropping into a clean white workspace. The system is 99% monochrome: pure white canvas, near-black text (#070709), pill-shaped dark CTAs, and 18px rounded cards floating on hairline shadows. One vivid blue (#2597d0) is reserved for functional punctuation — icons, micro-graphics, waveform players — never for buttons or large fills. Typography leans on Open Runde, a geometric humanist sans with aggressive negative tracking at display sizes (-0.04em at 80px) that tightens headlines into confident blocks. Components feel medical-instrument light: thin borders, generous card padding, pill buttons, and a reserved use of elevation that lets the sky hero do the emotional work.