:root{--color-bg:#fdf6ec;--color-text:#2d2a26;--color-accent:#c2571b;--color-user:#1b6ec2}*{box-sizing:border-box}body{margin:0;background-color:var(--color-bg);color:var(--color-text);font-family:Georgia,Times New Roman,serif;font-size:17px;line-height:1.5}.chat{max-width:720px;margin:0 auto;height:100dvh;display:flex;flex-direction:column;padding:16px}.chat__header{display:flex;align-items:baseline;justify-content:space-between;gap:16px;border-bottom:3px solid var(--color-accent);padding-bottom:12px}.chat__header h1{color:var(--color-accent);font-weight:400;margin:0;font-size:28px}.chat__lesson{font-size:14px;display:flex;align-items:center;gap:6px}.chat__lesson select{font:inherit;font-size:14px;padding:2px 4px}.chat__messages{flex:1 1;overflow-y:auto;padding:16px 0;display:flex;flex-direction:column;gap:12px}.chat__empty{color:#8a8378;font-style:italic;margin:auto 0;text-align:center}.bubble{max-width:85%;padding:10px 14px;border-radius:14px;white-space:pre-wrap;word-wrap:break-word}.bubble--user{align-self:flex-end;background-color:var(--color-user);color:var(--color-bg)}.bubble--assistant{align-self:flex-start;background-color:#fff;border:1px solid #e7ddc9}.chat__error{color:#b00020;font-size:14px;text-align:center}.chat__form{display:flex;gap:8px;padding-top:12px;border-top:1px solid #e7ddc9}.chat__form input{flex:1 1;font:inherit;padding:10px 12px;border:1px solid #cbbfa6;border-radius:10px;background:#fff}.chat__form button{font:inherit;padding:10px 18px;border:none;border-radius:10px;background-color:var(--color-accent);color:var(--color-bg);cursor:pointer}.chat__form button:disabled{opacity:.5;cursor:default}