:root{
  --primary:#4a7aff;
  --primary-dark:#3565e0;
  --primary-soft:#e8efff;
  --bg:#f4f6fb;
  --card:#ffffff;
  --ink:#1c2333;
  --muted:#8a92a6;
  --line:#e6eaf2;
  --good:#22b07d;
  --good-soft:#e4f7ef;
  --warn:#f2a33c;
  --danger:#e85c5c;
  --radius:18px;
  --shadow:0 6px 20px rgba(60,80,160,.08);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;padding:0;height:100%}
body{
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  background:var(--bg);color:var(--ink);
  max-width:520px;margin:0 auto;
  min-height:100%;
  overflow-x:hidden;
}
[hidden]{display:none!important}

/* ---------- header ---------- */
.app-header{
  position:sticky;top:0;z-index:20;
  display:flex;align-items:center;justify-content:space-between;
  padding:14px 18px;background:rgba(255,255,255,.85);
  backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--line);
}
.app-header .logo{font-size:19px;font-weight:800;letter-spacing:.5px}
.app-header .logo small{font-weight:600;color:var(--muted);font-size:12px;margin-left:6px}
.hdr-right{display:flex;align-items:center;gap:10px}
.streak{
  display:flex;align-items:center;gap:4px;font-weight:700;font-size:14px;color:var(--warn);
  background:#fff4e0;padding:4px 10px;border-radius:20px;
}
.streak svg{width:16px;height:16px}

/* ---------- bottom nav ---------- */
.tabbar{
  position:fixed;bottom:0;left:0;right:0;z-index:20;
  max-width:520px;margin:0 auto;
  display:flex;background:#fff;border-top:1px solid var(--line);
  padding:6px 0 calc(6px + env(safe-area-inset-bottom));
}
.tabbar .tab{
  flex:1;display:flex;flex-direction:column;align-items:center;gap:2px;
  padding:6px 0;color:var(--muted);font-size:11px;font-weight:600;
  cursor:pointer;border:none;background:none;transition:color .2s;
}
.tabbar .tab svg{width:22px;height:22px}
.tabbar .tab.active{color:var(--primary)}

main{padding:16px 16px 90px}

/* ---------- sections / cards ---------- */
.view{display:none}
.view.active{display:block;animation:fade .25s ease}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.card{
  background:var(--card);border-radius:var(--radius);
  box-shadow:var(--shadow);padding:18px;margin-bottom:16px;
}
.card-title{font-size:16px;font-weight:800;margin:0 0 4px}
.card-sub{font-size:12.5px;color:var(--muted);margin:0 0 12px;line-height:1.6}

.hero{
  position:relative;border-radius:22px;overflow:hidden;color:#fff;
  background:linear-gradient(135deg,#4a7aff,#7a5cff);
  padding:24px 20px;margin-bottom:16px;box-shadow:0 10px 26px rgba(74,122,255,.35);
}
.hero .big{font-size:34px;font-weight:900;margin:6px 0 2px}
.hero .label{font-size:13px;opacity:.9}
.hero .hint{margin-top:10px;font-size:12.5px;background:rgba(255,255,255,.16);padding:8px 12px;border-radius:12px;line-height:1.6}
.year-ring{position:absolute;right:16px;top:20px;width:74px;height:74px}

/* progress bars */
.bar{height:9px;border-radius:6px;background:#eef1f7;overflow:hidden;margin-top:14px}
.bar>i{display:block;height:100%;border-radius:6px;background:linear-gradient(90deg,var(--primary),#7ad7ff);transition:width .5s}

/* stats row */
.stats{display:flex;gap:10px;margin-bottom:16px}
.stat{flex:1;background:var(--card);border-radius:14px;padding:12px;text-align:center;box-shadow:var(--shadow)}
.stat .n{font-size:22px;font-weight:900;color:var(--primary)}
.stat .t{font-size:11.5px;color:var(--muted);margin-top:2px}

/* today's word chips */
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{background:var(--primary-soft);color:var(--primary-dark);font-weight:700;padding:8px 12px;border-radius:12px;font-size:13px}

/* buttons */
.btn{
  display:flex;align-items:center;justify-content:center;gap:8px;width:100%;
  border:none;border-radius:14px;padding:14px;font-size:15px;font-weight:700;cursor:pointer;
  transition:transform .08s,opacity .2s;
}
.btn:active{transform:scale(.97)}
.btn.primary{background:linear-gradient(135deg,var(--primary),var(--primary-dark));color:#fff;box-shadow:0 6px 16px rgba(74,122,255,.35)}
.btn.good{background:var(--good);color:#fff}
.btn.ghost{background:var(--primary-soft);color:var(--primary-dark)}
.btn.outline{background:#fff;color:var(--ink);border:1.5px solid var(--line)}
.btn.danger-soft{background:#fdeeee;color:var(--danger)}
.btn.lg{padding:16px}
.btn:disabled{opacity:.5}

/* flashcards */
.flashcard{
  background:var(--card);border-radius:var(--radius);box-shadow:var(--shadow);
  padding:26px 20px;text-align:center;margin-bottom:16px;min-height:230px;
  display:flex;flex-direction:column;justify-content:center;
}
.flashcard .en{font-size:40px;font-weight:900;word-break:break-word;line-height:1.2}
.flashcard .ph{color:var(--primary);font-size:16px;margin-top:8px;font-style:italic}
.flashcard .meaning{font-size:18px;font-weight:700;margin-top:14px}
.flashcard .ex{color:var(--ink);font-size:15px;margin-top:16px;line-height:1.6;display:none}
.flashcard .ex-cn{color:var(--muted);font-size:13px;margin-top:4px;display:none}
.flashcard.revealed .ex,.flashcard.revealed .ex-cn{display:block}
.flashcard.revealed .meaning{color:var(--good)}

.speak-row{display:flex;gap:8px;margin-top:16px}
.speak-row .btn{flex:1}

.progress-dots{display:flex;gap:6px;justify-content:center;margin:12px 0}
.progress-dots i{width:8px;height:8px;border-radius:50%;background:#e4e8f1}
.progress-dots i.on{background:var(--primary)}

/* review cards */
.review-card{text-align:left;min-height:0;padding:22px 20px}
.review-card .en{font-size:26px;text-align:center}
.review-card .meaning{text-align:center;font-size:16px}
.rating-row{display:flex;gap:8px;margin-top:20px}
.rating-row .rate{flex:1;border:none;border-radius:12px;padding:13px 4px;font-size:12.5px;font-weight:700;cursor:pointer;background:#f0f2f8;color:var(--ink)}
.rate.r1{background:#ffe8e8;color:var(--danger)}
.rate.r3{background:var(--good-soft);color:var(--good)}

/* speak practice */
.speak-word{font-size:30px;font-weight:800;color:var(--primary)}
.listen-btn{
  width:84px;height:84px;border-radius:50%;border:none;margin:18px auto 8px;
  background:linear-gradient(135deg,var(--primary),#7ad7ff);color:#fff;cursor:pointer;
  display:flex;align-items:center;justify-content:center;box-shadow:0 8px 20px rgba(74,122,255,.4);
}
.listen-btn svg{width:34px;height:34px}
.listen-btn.pulse{animation:pulse 1.2s infinite}
@keyframes pulse{0%{box-shadow:0 0 0 0 rgba(74,122,255,.5)}70%{box-shadow:0 0 0 22px rgba(74,122,255,0)}100%{box-shadow:0 0 0 0 rgba(74,122,255,0)}}
.mic-hint{font-size:13px;color:var(--muted);text-align:center;margin:6px 0 16px}
.recog-out{
  min-height:60px;background:#f6f8fd;border-radius:14px;padding:14px;margin-bottom:14px;
  text-align:center;font-size:15px;color:var(--ink);display:flex;align-items:center;justify-content:center;
}
.dif-score{font-size:14px;font-weight:800;text-align:center;margin:4px 0 14px;min-height:22px}
.tips{background:#f0f4ff;border-radius:12px;padding:12px 14px;font-size:13px;color:#3a4a7d;line-height:1.7;border-left:4px solid var(--primary)}

/* calendar streak */
.cal{display:grid;grid-template-columns:repeat(7,1fr);gap:6px}
.cal .cell{aspect-ratio:1;border-radius:10px;background:#eef1f7;font-size:11px;color:var(--muted);display:flex;align-items:center;justify-content:center;font-weight:600}
.cal .cell.done{background:var(--good);color:#fff}
.cal .cell.today{outline:2px solid var(--primary)}
.cal .cell.dim{opacity:.4}

/* library */
.vocab-search{width:100%;border:1px solid var(--line);border-radius:12px;padding:12px 14px;font-size:15px;margin-bottom:14px;background:#fff}
.theme-group{margin-bottom:14px}
.theme-head{font-weight:800;font-size:14px;margin:0 0 8px;color:var(--primary-dark)}
.word-row{display:flex;align-items:center;gap:10px;background:#fff;padding:11px 14px;border-radius:12px;margin-bottom:6px;box-shadow:var(--shadow)}
.word-row .en{font-weight:700;font-size:14.5px}
.word-row .zh{color:var(--muted);font-size:12.5px;flex:1}
.word-row .tag{font-size:10.5px;color:var(--good);background:var(--good-soft);padding:2px 7px;border-radius:8px}
.word-row .tag.new{color:var(--primary);background:var(--primary-soft)}
.word-row .tag.due{color:var(--warn);background:#fff4e0}

/* toast */
#toast{position:fixed;left:50%;bottom:110px;transform:translateX(-50%);z-index:99;background:#1c2333;color:#fff;padding:10px 18px;border-radius:12px;font-size:14px;opacity:0;pointer-events:none;transition:opacity .25s;max-width:80%;text-align:center}
#toast.show{opacity:1}

/* install banner */
#installBanner{
  position:fixed;left:0;right:0;top:0;z-index:40;background:linear-gradient(135deg,#4a7aff,#7a5cff);
  color:#fff;padding:12px 18px;display:flex;align-items:center;gap:12px;font-size:14px;
}
#installBanner .f{flex:1}
#installBanner button{border:none;background:#fff;color:var(--primary-dark);font-weight:800;padding:8px 14px;border-radius:10px;cursor:pointer}

@media (min-width:521px){ .app-header,.tabbar{left:50%;transform:translateX(-50%)} }