.stats-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 12px; }
.stat-card { padding: 20px 16px; background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg); text-align: center; }
.stat-card .stat-val { font-size: 2rem; font-weight: 800; background: linear-gradient(135deg, var(--color-primary), var(--color-accent)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.stat-card .stat-label { font-size: .8rem; color: var(--color-text-secondary); margin-top: 4px; }
.detail-section { margin-top: 16px; }
.detail-section h5 { margin-bottom: 8px; color: var(--color-primary); }
.freq-bar { display: flex; align-items: center; gap: 8px; padding: 4px 0; }
.freq-word { width: 100px; font-family: monospace; font-weight: 600; }
.freq-fill { height: 12px; border-radius: 6px; background: linear-gradient(90deg, var(--color-primary), var(--color-accent)); }
.freq-count { font-size: .8rem; color: var(--color-text-secondary); }
.grade-badge { display: inline-block; padding: 4px 12px; border-radius: var(--radius-full); font-weight: 600; font-size: .85rem; }
.grade-easy { background: rgba(34,197,94,.15); color: #22c55e; }
.grade-medium { background: rgba(234,179,8,.15); color: #eab308; }
.grade-hard { background: rgba(239,68,68,.15); color: #ef4444; }