:root{--font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;--bg-primary: #f8fafc;--bg-card: #ffffff;--text-main: #1e293b;--text-muted: #64748b;--border-color: #e2e8f0;--accent-color: #6366f1}*{box-sizing:border-box;margin:0;padding:0}html,body{min-height:100%;font-family:var(--font-family);background:var(--bg-primary);color:var(--text-main);-webkit-tap-highlight-color:transparent}body{display:flex;flex-direction:column}.top-nav{position:sticky;top:0;left:0;right:0;z-index:100;background:#fffffff2;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--border-color);padding:8px 16px}.nav-container{max-width:1200px;margin:0 auto;display:flex;justify-content:space-between;align-items:center}.nav-logo{display:flex;align-items:center;text-decoration:none;color:#1f2937;font-weight:700;font-size:16px;gap:8px;transition:opacity .2s ease}.nav-logo:hover{opacity:.85}.nav-logo img{width:26px;height:26px;border-radius:50%}.nav-links{display:flex;gap:14px;align-items:center}.nav-link{color:#64748b;text-decoration:none;font-size:12px;transition:color .2s ease}.nav-link:hover{color:var(--accent-color)}.main-wrapper{max-width:1100px;margin:0 auto;padding:14px 14px 28px;flex:1;width:100%;display:flex;flex-direction:column;justify-content:flex-start}.alphabet-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:10px;width:100%;margin:0}.letter-card{background:var(--bg-card);border:1.5px solid var(--border-color);border-radius:12px;padding:8px 6px;display:flex;flex-direction:column;align-items:center;justify-content:center;position:relative;cursor:pointer;-webkit-user-select:none;user-select:none;transition:border-color .15s ease,box-shadow .15s ease,background-color .15s ease;box-shadow:0 1px 4px #0000000a;overflow:hidden;min-height:84px}.letter-card:before{content:"";position:absolute;top:0;left:0;right:0;height:3px;background:var(--card-color, #6366f1);border-radius:12px 12px 0 0;opacity:.9}.letter-card:hover{border-color:#94a3b8}.letter-card:active{transform:scale(.97)}.letter-card.speaking{border-color:var(--card-color, #6366f1);box-shadow:0 0 0 2.5px #6366f14d;background:#fff}.letter-glyph{font-weight:800;color:#1e293b;line-height:1.1;margin:2px 0 3px;font-family:"SF Pro Rounded","Arial Rounded MT Bold",var(--font-family);display:flex;align-items:baseline;gap:3px;transition:color .15s ease}.letter-upper{font-size:26px}.letter-lower{font-size:19px;opacity:.85}.letter-card.speaking .letter-glyph{color:var(--card-color, #4f46e5)}.letter-ipa{font-size:11px;font-weight:600;color:#64748b;background:#f1f5f9;padding:1px 7px;border-radius:8px;margin-bottom:5px;letter-spacing:.02em;line-height:1.3}.letter-word-row{display:flex;align-items:center;justify-content:center;gap:4px;font-size:11.5px;font-weight:600;color:#334155;width:100%;line-height:1.2}.word-emoji{font-size:13px;line-height:1}.word-text{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.sound-indicator{position:absolute;top:5px;right:6px;opacity:0;transform:scale(.65);transition:opacity .15s ease;color:var(--card-color, #4f46e5)}.letter-card.speaking .sound-indicator{opacity:1;transform:scale(.85)}@media (max-width: 860px){.alphabet-grid{grid-template-columns:repeat(7,1fr);gap:7px}.letter-card{padding:6px 4px;min-height:76px;border-radius:10px}.letter-upper{font-size:22px}.letter-lower{font-size:16px}.letter-ipa{font-size:10px;padding:1px 5px;margin-bottom:3px}.letter-word-row{font-size:10.5px}.word-emoji{font-size:12px}}@media (max-width: 640px){.main-wrapper{padding:10px 10px 24px;justify-content:flex-start}.alphabet-grid{grid-template-columns:repeat(4,1fr);gap:8px;margin:0}.letter-card{padding:8px 4px;min-height:72px;border-radius:11px}.letter-glyph{margin:1px 0 2px}.letter-upper{font-size:22px}.letter-lower{font-size:16px}.letter-ipa{font-size:10.5px;padding:1px 6px;margin-bottom:3px}.letter-word-row{font-size:11px;gap:3px}.word-emoji{font-size:13px}}