:root {
  --bg: #0e1220;
  --bg-soft: #161c2e;
  --card: #1a2136;
  --card-2: #212a44;
  --line: #2b3550;
  --text: #eef2ff;
  --muted: #98a3c0;
  --accent: #5ce1a4;
  --accent-dark: #173d31;
  --accent-2: #7aa2ff;
  --wrong: #ff6b81;
  --wrong-dark: #3a1c26;
  --radius: 16px;
  --font: "Segoe UI", system-ui, -apple-system, "Inter", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--font);
  background:
    radial-gradient(900px 500px at 12% -10%, #1d2b4d 0%, transparent 65%),
    radial-gradient(700px 400px at 95% 0%, #1b3a35 0%, transparent 60%),
    var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

hidden, .hidden { display: none !important; }

/* ---------- header ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px clamp(16px, 4vw, 48px) 12px;
  flex-wrap: wrap;
}

.brand { display: flex; align-items: center; gap: 14px; }

a.brand { color: inherit; text-decoration: none; border-radius: 12px; }
a.brand:hover h1 { color: var(--accent); }
a.brand:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }

.logo {
  width: 44px; height: 44px;
  flex: 0 0 44px;
}

.brand h1 { margin: 0; font-size: 21px; letter-spacing: .2px; }
.tag { margin: 2px 0 0; font-size: 12.5px; color: var(--muted); }

.topstats { display: flex; gap: 10px; }

.stat {
  background: rgba(255, 255, 255, .04);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 8px 14px;
  text-align: center;
  min-width: 72px;
}
.stat span { display: block; font-weight: 700; font-size: 17px; }
.stat small { color: var(--muted); font-size: 10.5px; letter-spacing: .4px; text-transform: uppercase; }

/* ---------- tabs ---------- */
.tabs {
  display: flex;
  gap: 6px;
  padding: 6px clamp(16px, 4vw, 48px) 0;
  border-bottom: 1px solid var(--line);
  max-width: 1080px;
  margin: 0 auto;
  position: sticky;
  top: 0;
  background: rgba(14, 18, 32, .85);
  backdrop-filter: blur(10px);
  z-index: 20;
}

.tab {
  background: none;
  border: 0;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  font: inherit;
  font-weight: 600;
  font-size: 14.5px;
  padding: 12px 15px;
  cursor: pointer;
}
.tab:hover { color: var(--text); }
.tab.active { color: var(--accent); border-bottom-color: var(--accent); }

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 26px clamp(16px, 4vw, 48px) 70px;
}

.view { display: none; }
.view.active { display: block; animation: fade .18s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

/* ---------- cards & controls ---------- */
.card {
  background: linear-gradient(180deg, var(--card), var(--bg-soft));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: 0 18px 45px rgba(0, 0, 0, .28);
}

h2 { margin: 0 0 8px; font-size: 19px; }
.muted { color: var(--muted); }
.small-note { font-size: 12.5px; margin: 14px 0 0; }

.field { margin: 20px 0; }
.field > label {
  display: block;
  font-size: 11.5px;
  letter-spacing: .8px;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 9px;
  font-weight: 700;
}

.chips { display: flex; flex-wrap: wrap; gap: 8px; }

.chip {
  background: rgba(255, 255, 255, .03);
  border: 1px solid var(--line);
  color: var(--muted);
  border-radius: 999px;
  padding: 8px 15px;
  font: inherit;
  font-size: 13.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all .14s ease;
}
.chip:hover { color: var(--text); border-color: #3d4a6d; }
.chip.active {
  background: var(--accent-dark);
  border-color: var(--accent);
  color: var(--accent);
}

.toggle {
  display: flex; align-items: center; gap: 10px;
  font-size: 13.5px; color: var(--muted);
  margin: 6px 0 22px;
  cursor: pointer;
}
.toggle input { width: 17px; height: 17px; accent-color: var(--accent); cursor: pointer; }

button.primary {
  background: linear-gradient(145deg, #6ef0b4, #43c894);
  border: 0;
  color: #06231a;
  font: inherit;
  font-weight: 800;
  padding: 12px 22px;
  border-radius: 12px;
  cursor: pointer;
  box-shadow: 0 10px 26px rgba(92, 225, 164, .22);
  transition: transform .12s ease, filter .12s ease;
}
button.primary:hover { filter: brightness(1.06); }
button.primary:active { transform: translateY(1px); }
button.big { width: 100%; padding: 15px; font-size: 15.5px; margin-top: 6px; }

button.ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--muted);
  font: inherit;
  font-weight: 600;
  padding: 11px 18px;
  border-radius: 12px;
  cursor: pointer;
  margin-top: 12px;
}
button.ghost:hover { color: var(--text); border-color: #3d4a6d; }
button.ghost.small { padding: 6px 12px; font-size: 12.5px; margin: 0; }
button.ghost.danger:hover { color: var(--wrong); border-color: var(--wrong); }

/* ---------- quiz ---------- */
.quiz-head { margin-bottom: 16px; }

.progressbar {
  height: 7px;
  background: var(--card-2);
  border-radius: 99px;
  overflow: hidden;
}
#bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-2), var(--accent));
  border-radius: 99px;
  transition: width .25s ease;
}

.quiz-meta {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-top: 10px;
  font-size: 13px;
  color: var(--muted);
}
.quiz-meta button { margin-left: auto; }

.question-card { padding: 26px; }

.q-top { display: flex; gap: 8px; align-items: center; margin-bottom: 16px; flex-wrap: wrap; }

.badge {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .5px;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(122, 162, 255, .16);
  color: #a9c2ff;
  text-transform: uppercase;
}
.ghost-badge { background: rgba(255, 255, 255, .05); color: var(--muted); text-transform: none; letter-spacing: 0; }

.prompt {
  font-size: clamp(22px, 3.2vw, 30px);
  line-height: 1.35;
  margin: 6px 0 6px;
  font-weight: 700;
}
.prompt.cloze-blank { color: var(--accent-2); }
.prompt-sub { color: var(--muted); margin: 0 0 20px; font-size: 14.5px; }
.prompt-sub em { color: #cfd8f5; font-style: italic; }

.speak {
  background: rgba(122, 162, 255, .14);
  border: 1px solid #33456e;
  color: #a9c2ff;
  border-radius: 10px;
  width: 38px; height: 38px;
  font-size: 16px;
  cursor: pointer;
  margin-bottom: 14px;
}

.options { display: grid; gap: 10px; margin-top: 6px; }

.option {
  display: flex;
  align-items: center;
  gap: 12px;
  text-align: left;
  background: rgba(255, 255, 255, .03);
  border: 1px solid var(--line);
  color: var(--text);
  font: inherit;
  font-size: 15px;
  padding: 15px 16px;
  border-radius: 13px;
  cursor: pointer;
  transition: background .13s, border-color .13s, transform .1s;
}
.option:hover:not(:disabled) { background: rgba(255, 255, 255, .06); border-color: #3f4d72; }
.option:active:not(:disabled) { transform: scale(.995); }
.option .key {
  width: 24px; height: 24px;
  flex: 0 0 24px;
  display: grid; place-items: center;
  border-radius: 7px;
  background: rgba(255, 255, 255, .07);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}
.option.correct { background: var(--accent-dark); border-color: var(--accent); color: #d8fff0; }
.option.correct .key { background: var(--accent); color: #06231a; }
.option.wrong { background: var(--wrong-dark); border-color: var(--wrong); color: #ffe0e5; }
.option.wrong .key { background: var(--wrong); color: #2a0b11; }
.option:disabled { cursor: default; }
.option.dim { opacity: .45; }

.typebox { display: flex; gap: 10px; margin-top: 8px; }
.typebox input {
  flex: 1;
  background: rgba(0, 0, 0, .28);
  border: 1px solid var(--line);
  color: var(--text);
  font: inherit;
  font-size: 16px;
  padding: 13px 15px;
  border-radius: 12px;
  outline: none;
}
.typebox input:focus { border-color: var(--accent-2); }

.feedback {
  margin-top: 20px;
  border-top: 1px solid var(--line);
  padding-top: 16px;
}
.feedback p { margin: 0 0 8px; font-size: 15px; font-weight: 600; }
.feedback .fb-detail { font-weight: 400; font-size: 13.5px; line-height: 1.6; margin-bottom: 14px; }
.feedback.good p:first-child { color: var(--accent); }
.feedback.bad p:first-child { color: var(--wrong); }

/* ---------- summary ---------- */
.summary { text-align: center; margin-top: 20px; }
.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 20px 0;
}
.summary-grid.wide { grid-template-columns: repeat(4, 1fr); }
.summary-grid > div {
  background: rgba(255, 255, 255, .04);
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 16px 10px;
}
.summary-grid span { display: block; font-size: 25px; font-weight: 800; color: var(--accent); }
.summary-grid small { color: var(--muted); font-size: 11.5px; letter-spacing: .3px; }

.missed-list { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; margin-bottom: 20px; }
.missed-list span {
  background: var(--wrong-dark);
  border: 1px solid #5c2b38;
  color: #ffc2cc;
  border-radius: 999px;
  padding: 5px 12px;
  font-size: 12.5px;
}

/* ---------- library ---------- */
.lib-toolbar { display: grid; gap: 12px; margin-bottom: 14px; }
#search {
  width: 100%;
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--text);
  font: inherit;
  font-size: 15px;
  padding: 14px 16px;
  border-radius: 13px;
  outline: none;
}
#search:focus { border-color: var(--accent-2); }
.count { font-size: 13px; margin: 0 0 12px; }

.word-list { display: grid; gap: 10px; margin-bottom: 16px; }

.word-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 13px;
  padding: 15px 17px;
}
.word-card .wc-head {
  display: flex;
  align-items: baseline;
  gap: 9px;
  flex-wrap: wrap;
}
.wc-word { font-size: 17px; font-weight: 700; }
.wc-pos { color: var(--accent-2); font-size: 12px; font-style: italic; }
.wc-def { margin: 6px 0 4px; font-size: 14px; line-height: 1.55; }
.wc-ex { margin: 0; font-size: 13px; color: var(--muted); font-style: italic; }
.wc-syn { margin: 5px 0 0; font-size: 12px; color: #7f8aa8; }
.wc-head .spacer { flex: 1; }
.wc-actions { display: flex; gap: 6px; align-items: center; }
.icon-btn {
  background: transparent;
  border: 1px solid transparent;
  color: #5f6a88;
  font-size: 15px;
  cursor: pointer;
  border-radius: 8px;
  padding: 2px 6px;
  line-height: 1;
}
.icon-btn:hover { color: var(--text); border-color: var(--line); }
.icon-btn.on { color: #ffd166; }
.status-dot {
  width: 8px; height: 8px;
  border-radius: 99px;
  display: inline-block;
  margin-left: 2px;
}
.dot-new { background: #3f4a68; }
.dot-learning { background: #ffb703; }
.dot-known { background: var(--accent); }

/* ---------- progress ---------- */
.level-bars { display: grid; gap: 14px; margin: 24px 0 6px; }
.level-row { display: grid; grid-template-columns: 92px 1fr 60px; align-items: center; gap: 12px; font-size: 13px; }
.level-row span:last-child { text-align: right; color: var(--muted); font-size: 12px; }
.track { height: 8px; background: var(--card-2); border-radius: 99px; overflow: hidden; }
.track > div { height: 100%; background: linear-gradient(90deg, var(--accent-2), var(--accent)); border-radius: 99px; transition: width .3s; }

.row-buttons { display: flex; gap: 10px; flex-wrap: wrap; }

@media (max-width: 620px) {
  .summary-grid.wide { grid-template-columns: repeat(2, 1fr); }
  .topstats { width: 100%; justify-content: space-between; }
  .stat { flex: 1; }
  .quiz-meta { flex-wrap: wrap; }
}