:root{--sidebar-width: 240px;--content-max: 760px;--accent: rgb(24, 131, 215);--link: #1a6bb5;--toggle: #d97a00;--text: #1b1b1b;--muted: #555}*{box-sizing:border-box}body{margin:0;font-family:Source Sans Pro,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;font-size:18px;line-height:1.6;color:var(--text)}a{color:var(--link);text-decoration:none;transition:color .3s ease}a:hover{text-decoration:underline}.layout{display:flex;align-items:flex-start}.sidebar{position:fixed;top:0;right:0;width:var(--sidebar-width);padding:40px 24px;height:100vh;overflow-y:auto}.content{margin-right:var(--sidebar-width);padding:40px clamp(20px,5vw,60px) 120px;max-width:var(--content-max);width:100%}.sidebar__logo{width:80px;height:50px;object-fit:cover}.sidebar__name{margin:8px 0 20px;font-size:22px}.sidebar__heading{font-weight:700;margin:18px 0 6px}.sidebar__nav{display:flex;flex-direction:column;gap:6px}.sidebar__current{padding-left:8px;border-left:3px solid var(--accent);color:var(--text);font-weight:600}.back-link{display:inline-block;margin:4px 0 16px}.content h2,.content h3{line-height:1.25}.content img{max-width:100%;height:auto}.app-img{width:40%}.toggle-btn{color:var(--toggle);cursor:pointer;-webkit-user-select:none;user-select:none;display:inline-block;margin:4px 0}.toggle-btn:before{content:"▸ ";display:inline-block;transition:transform .15s ease}.toggle-btn--open:before{content:"▾ "}.toggle-body{padding-left:15px;border-left:1px solid var(--toggle);margin:4px 0 12px}.toggle-inline{color:var(--toggle);cursor:pointer;-webkit-user-select:none;user-select:none}#pong_pic{border-bottom:1px solid var(--accent)}@media (max-width: 800px){.sidebar{display:none}.content{margin-right:0;max-width:100%;padding:24px 18px 80px}.app-img{width:80%}}