:root{--bg: #f5f3f0;--surface: #ffffff;--border: #e2ddd8;--text: #1a1917;--muted: #6b6762;--accent: #c96b1a;--radius: 8px;--font: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;--heat-0: #e2ddd8;--heat-1: #f0c89a;--heat-2: #e0a050;--heat-3: #cc7828;--heat-4: #c96b1a}[data-theme=dark]{--bg: #111110;--surface: #1c1b1a;--border: #2e2c2a;--text: #ededeb;--muted: #8c8a87;--accent: #e07c28;--heat-0: #2e2c2a;--heat-1: #3d2810;--heat-2: #6b4020;--heat-3: #a05c20;--heat-4: #e07c28}*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font);font-size:14px;line-height:1.5;background:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased}.app{min-height:100vh}.app-main{padding:32px 0 64px}.container{max-width:900px;margin:0 auto;padding:0 24px}.site-header{margin-bottom:8px}.header-banner{position:relative;height:180px;overflow:hidden;background:var(--border)}.header-bg{width:100%;height:100%;object-fit:cover;display:block}.theme-toggle{position:absolute;top:12px;right:16px;background:#00000059;border:none;cursor:pointer;color:#fff;font-size:16px;padding:6px 8px;border-radius:50%;line-height:1;transition:background .15s}.theme-toggle:hover{background:#0000008c}.header-profile{max-width:900px;margin:0 auto;padding:0 24px 20px;position:relative;z-index:1}.profile-pic{width:80px;height:80px;border-radius:var(--radius);border:3px solid var(--bg);display:block;margin-top:-40px;background:var(--surface);object-fit:cover}.header-meta{margin-top:12px}.author-name{font-size:20px;font-weight:600;line-height:1.2}.book-title{margin-top:2px;font-size:14px}.session-count{margin-top:6px;font-size:13px}.muted{color:var(--muted)}.activity-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px 24px 16px}.heatmap-wrapper{display:flex;flex-direction:column;gap:8px}.heatmap-scroll{overflow-x:auto}.heatmap-label{font-family:var(--font);font-size:10px;fill:var(--muted)}.heat-cell{cursor:default}.heat-cell.level-0{fill:var(--heat-0)}.heat-cell.level-1{fill:var(--heat-1)}.heat-cell.level-2{fill:var(--heat-2)}.heat-cell.level-3{fill:var(--heat-3)}.heat-cell.level-4{fill:var(--heat-4)}.heat-cell.level-future{fill:none;stroke:var(--border);stroke-width:.5}.heatmap-tooltip{position:fixed;pointer-events:none;background:var(--text);color:var(--bg);font-size:12px;line-height:1.5;padding:6px 10px;border-radius:6px;white-space:nowrap;z-index:100;transform:translateY(-100%);margin-top:-4px}.heatmap-legend{display:flex;align-items:center;gap:4px;justify-content:flex-end}.status-text{color:var(--muted);font-size:15px;padding:48px 0;text-align:center}.status-text.error{color:#b03030}@media (max-width: 640px){.header-banner{height:120px}.activity-card{padding:16px 16px 12px}}