@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Sans+KR:wght@400;500;600;700;800&family=Lexend:wght@400;500;600;700&display=swap');

:root {
  color-scheme: light;
  --bg-0: #eef7ff;
  --bg-1: #dceeff;
  --bg-2: #f8fbff;
  --surface: rgba(255, 255, 255, 0.82);
  --surface-strong: rgba(255, 255, 255, 0.94);
  --ink: #08213f;
  --muted: #5b718c;
  --soft: #d7e7f8;
  --line: rgba(36, 99, 166, 0.16);
  --line-strong: rgba(28, 88, 155, 0.26);
  --blue: #2563eb;
  --blue-2: #0ea5e9;
  --blue-3: #1d4ed8;
  --cyan: #67e8f9;
  --green: #16a78a;
  --amber: #e59a12;
  --red: #e05252;
  --shadow: 0 28px 90px rgba(15, 67, 129, 0.18);
  --shadow-soft: 0 18px 50px rgba(22, 92, 163, 0.13);
  --radius-xl: 32px;
  --radius-lg: 24px;
  --radius-md: 18px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  font-family: "IBM Plex Sans KR", ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 6%, rgba(14, 165, 233, 0.28), transparent 28rem),
    radial-gradient(circle at 88% 10%, rgba(37, 99, 235, 0.22), transparent 30rem),
    linear-gradient(145deg, var(--bg-2) 0%, var(--bg-0) 46%, #eaf3ff 100%);
  overflow-x: hidden;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(37, 99, 235, .035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(37, 99, 235, .035) 1px, transparent 1px);
  background-size: 42px 42px;
  mask-image: linear-gradient(to bottom, #000 0%, transparent 78%);
}
a { color: inherit; }
button, input { font: inherit; }
button { min-height: 46px; }
button:focus-visible, a:focus-visible, input:focus-visible {
  outline: 3px solid rgba(14, 165, 233, .42);
  outline-offset: 3px;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  padding: 1rem clamp(1rem, 4vw, 2.35rem);
  background: rgba(238, 247, 255, 0.72);
  backdrop-filter: blur(22px) saturate(1.2);
  border-bottom: 1px solid var(--line);
}
.topbar h1 {
  margin: .12rem 0 0;
  font-size: clamp(1.42rem, 5vw, 2.35rem);
  letter-spacing: -.055em;
  line-height: 1.05;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  color: var(--blue-3);
  font-size: .72rem;
  font-weight: 900;
  letter-spacing: .14em;
}
.eyebrow::before {
  content: "";
  width: .55rem;
  height: .55rem;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  box-shadow: 0 0 0 6px rgba(14, 165, 233, .12);
}
nav { display: flex; gap: .52rem; flex-wrap: wrap; justify-content: flex-end; }
nav a {
  min-height: 42px;
  display: inline-grid;
  place-items: center;
  padding: .58rem .82rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  text-decoration: none;
  background: rgba(255,255,255,.64);
  color: #174069;
  font-size: .92rem;
  font-weight: 850;
  box-shadow: 0 10px 26px rgba(17, 83, 151, .08);
  transition: transform .18s ease, border-color .18s ease, background .18s ease;
}
nav a:hover { transform: translateY(-1px); border-color: var(--line-strong); background: #fff; }

.app {
  position: relative;
  max-width: 980px;
  margin: 0 auto;
  padding: 1.15rem clamp(.95rem, 3vw, 1.35rem) 5rem;
}
.hero {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  align-items: center;
  margin: .55rem 0 1.05rem;
  padding: clamp(1rem, 3vw, 1.35rem);
  border: 1px solid rgba(255,255,255,.75);
  border-radius: var(--radius-xl);
  background:
    linear-gradient(135deg, rgba(255,255,255,.93), rgba(224, 242, 254, .66)),
    radial-gradient(circle at 100% 0%, rgba(103, 232, 249, .42), transparent 20rem);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  right: -3.5rem;
  top: -3.8rem;
  width: 11rem;
  height: 11rem;
  border-radius: 999px;
  background: radial-gradient(circle, rgba(37, 99, 235, .16), transparent 68%);
}
.hero p { margin: .28rem 0; color: var(--muted); line-height: 1.55; }
.progress-text { font-weight: 760; color: #355b82 !important; }
.progress-ring {
  position: relative;
  min-width: 82px;
  height: 82px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: conic-gradient(var(--blue) var(--pct, 0%), rgba(37, 99, 235, .11) 0);
  font-weight: 950;
  color: var(--blue-3);
  box-shadow: inset 0 0 0 1px rgba(37, 99, 235, .10), 0 16px 38px rgba(37, 99, 235, .18);
}
.progress-ring span {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--surface-strong);
  display: grid;
  place-items: center;
  font-size: .9rem;
  letter-spacing: -.03em;
}
.status {
  margin: .8rem 0;
  color: var(--muted);
  line-height: 1.6;
}
.cards { display: grid; gap: 1rem; padding-bottom: 4rem; }
.card {
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: var(--radius-xl);
  background: var(--surface);
  box-shadow: var(--shadow);
  overflow: hidden;
  backdrop-filter: blur(18px) saturate(1.1);
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: 0 34px 100px rgba(15, 67, 129, .22); border-color: rgba(37,99,235,.22); }
.card-main { padding: clamp(1.05rem, 3vw, 1.35rem); }
.card-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 1rem; }
.word {
  font-family: "Lexend", "IBM Plex Sans KR", ui-sans-serif, system-ui, sans-serif;
  font-size: clamp(1.9rem, 8vw, 3.05rem);
  font-weight: 700;
  letter-spacing: -.018em;
  line-height: 1.08;
  color: #03172d;
}
.reading { margin-top: .32rem; color: var(--muted); font-size: 1.05rem; font-weight: 600; letter-spacing: -.006em; }
.meta { display: flex; gap: .45rem; flex-wrap: wrap; margin-top: .55rem; }
.badge {
  min-height: 26px;
  display: inline-grid;
  place-items: center;
  padding: .26rem .58rem;
  border-radius: 999px;
  background: rgba(14, 165, 233, .10);
  color: #075985;
  border: 1px solid rgba(14, 165, 233, .14);
  font-size: .78rem;
  font-weight: 850;
}
.badge:empty { display: none; }
.position {
  flex: 0 0 auto;
  color: #2b6aa8;
  font-weight: 950;
  font-size: .86rem;
  padding: .38rem .62rem;
  border-radius: 999px;
  background: rgba(219, 234, 254, .74);
  border: 1px solid rgba(37, 99, 235, .12);
}
.meaning {
  margin: 1.05rem 0 .68rem;
  font-size: 1.3rem;
  font-weight: 800;
  letter-spacing: -.018em;
  color: #0d355f;
}
.example {
  margin: .65rem 0 0;
  color: #0f2e4d;
  font-family: "Lexend", "IBM Plex Sans KR", ui-sans-serif, system-ui, sans-serif;
  font-size: 1.04rem;
  line-height: 1.68;
  font-weight: 400;
}
.example-ko { margin: .32rem 0 0; color: #506985; line-height: 1.72; font-weight: 400; letter-spacing: -.006em; }
.reveal {
  margin-top: 1rem;
  padding: .78rem 1rem;
  border: 1px solid rgba(37, 99, 235, .16);
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #ffffff, #edf7ff);
  color: #174069;
  font-weight: 900;
  cursor: pointer;
  box-shadow: 0 12px 28px rgba(17, 83, 151, .09);
  transition: transform .16s ease, border-color .16s ease;
}
.reveal:hover { transform: translateY(-1px); border-color: rgba(37, 99, 235, .32); }
.detail {
  margin-top: .95rem;
  padding: 1rem;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(239, 248, 255, .9), rgba(255,255,255,.66));
  border: 1px solid rgba(37, 99, 235, .12);
}
.hidden-detail { display: none; }
.actions {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: .58rem;
  padding: .82rem;
  background: rgba(230, 242, 255, .72);
  border-top: 1px solid var(--line);
}
.actions button, .login-card button {
  border: 0;
  border-radius: var(--radius-md);
  padding: .82rem .55rem;
  color: #fff;
  font-weight: 950;
  cursor: pointer;
  box-shadow: 0 14px 32px rgba(15, 67, 129, .16);
  transition: transform .16s ease, opacity .16s ease, filter .16s ease;
}
.actions button:hover, .login-card button:hover { transform: translateY(-1px); }
.known { background: linear-gradient(135deg, #19b894, #0f8f78); }
.uncertain { background: linear-gradient(135deg, #f3b536, #d68508); }
.unknown { background: linear-gradient(135deg, #f26868, #cf3f3f); }
button.inactive { opacity: .38; filter: saturate(.65); }
button:disabled { cursor: wait; opacity: .62; }
.empty {
  padding: 1.25rem;
  border: 1px dashed rgba(37, 99, 235, .25);
  border-radius: var(--radius-lg);
  background: rgba(255,255,255,.64);
  color: var(--muted);
  line-height: 1.75;
  box-shadow: var(--shadow-soft);
}

.login-body {
  display: grid;
  place-items: center;
  padding: 1rem;
  min-height: 100vh;
}
.login-shell {
  width: min(960px, 100%);
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 1rem;
  align-items: stretch;
}
.login-visual, .login-card {
  border: 1px solid rgba(255,255,255,.78);
  border-radius: 34px;
  background: rgba(255,255,255,.72);
  box-shadow: var(--shadow);
  backdrop-filter: blur(22px) saturate(1.16);
}
.login-visual {
  position: relative;
  overflow: hidden;
  padding: clamp(1.25rem, 4vw, 2rem);
  min-height: 500px;
  background:
    radial-gradient(circle at 76% 16%, rgba(103, 232, 249, .42), transparent 15rem),
    linear-gradient(150deg, rgba(255,255,255,.86), rgba(219, 234, 254, .70));
}
.login-visual::after {
  content: "";
  position: absolute;
  inset: auto -4rem -5rem auto;
  width: 16rem;
  height: 16rem;
  border-radius: 999px;
  background: radial-gradient(circle, rgba(37, 99, 235, .20), transparent 70%);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  color: var(--blue-3);
  font-weight: 950;
  letter-spacing: .11em;
  font-size: .78rem;
}
.brand::before {
  content: "";
  width: .65rem;
  height: .65rem;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  box-shadow: 0 0 0 7px rgba(14,165,233,.12);
}
.login-title {
  margin: 1.15rem 0 .9rem;
  max-width: 28rem;
  font-size: clamp(2.05rem, 6.3vw, 3.95rem);
  line-height: 1.08;
  letter-spacing: -.045em;
  font-weight: 900;
  color: #061c36;
  text-wrap: balance;
}
.login-copy { margin: 0; max-width: 29rem; color: #506985; line-height: 1.82; font-weight: 500; letter-spacing: -.01em; }
.login-preview {
  position: relative;
  margin-top: 2rem;
  display: grid;
  gap: .78rem;
  max-width: 24rem;
}
.preview-card {
  padding: 1rem;
  border-radius: 24px;
  background: rgba(255,255,255,.78);
  border: 1px solid rgba(37,99,235,.12);
  box-shadow: 0 20px 48px rgba(15,67,129,.12);
}
.preview-card:nth-child(2) { margin-left: 2.2rem; }
.preview-label { color: var(--blue-3); font-size: .76rem; font-weight: 950; letter-spacing: .08em; }
.preview-word { margin-top: .35rem; font-family: "Lexend", "IBM Plex Sans KR", ui-sans-serif, system-ui, sans-serif; font-size: 1.55rem; font-weight: 600; letter-spacing: -.006em; }
.preview-meaning { margin-top: .25rem; color: #506985; font-weight: 500; letter-spacing: -.01em; }
.login-card {
  width: 100%;
  padding: clamp(1.15rem, 4vw, 1.65rem);
  align-self: center;
  background: rgba(255,255,255,.88);
}
.login-card h1 { margin: .75rem 0 .45rem; font-size: clamp(1.6rem, 6vw, 2.35rem); letter-spacing: -.055em; }
.login-card p { color: var(--muted); line-height: 1.65; }
.login-card input {
  width: 100%;
  min-height: 54px;
  padding: 1rem;
  margin: .85rem 0 .7rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(239, 248, 255, .72);
  color: var(--ink);
  font-size: 1rem;
}
.login-card button { width: 100%; background: linear-gradient(135deg, var(--blue), var(--blue-2)); }
.login-note {
  margin-top: .9rem;
  padding: .8rem .9rem;
  border-radius: 18px;
  background: rgba(219, 234, 254, .62);
  color: #315b86 !important;
  font-size: .9rem;
}
.error {
  color: var(--red) !important;
  font-weight: 850;
  background: rgba(224, 82, 82, .08);
  border: 1px solid rgba(224, 82, 82, .18);
  padding: .7rem .8rem;
  border-radius: 16px;
}


.word-row { display: flex; align-items: center; gap: .65rem; flex-wrap: wrap; }
.audio {
  min-height: 34px;
  border: 1px solid rgba(37, 99, 235, .18);
  border-radius: 999px;
  padding: .35rem .7rem;
  background: rgba(255,255,255,.82);
  color: #174069;
  font-size: .82rem;
  font-weight: 700;
  cursor: pointer;
}
.audio-inline { margin-top: .8rem; }
.quiz-options { display: grid; gap: .62rem; margin-top: 1rem; }
.quiz-option {
  min-height: 48px;
  border: 1px solid rgba(37, 99, 235, .15);
  border-radius: 16px;
  background: rgba(255,255,255,.9);
  color: #123a63;
  font-weight: 700;
  cursor: pointer;
}
.quiz-option.correct { background: rgba(22, 167, 138, .16); border-color: rgba(22, 167, 138, .45); color: #08715e; }
.quiz-option.wrong { background: rgba(224, 82, 82, .14); border-color: rgba(224, 82, 82, .38); color: #b22f2f; }
.quiz-result { margin-top: .75rem; color: #315b86; font-weight: 700; }
.small-link {
  display: inline-grid;
  place-items: center;
  min-height: 38px;
  padding: .45rem .75rem;
  border-radius: 999px;
  background: rgba(219, 234, 254, .8);
  color: #174069;
  text-decoration: none;
  font-weight: 700;
}
.word-cloud { display: flex; flex-wrap: wrap; gap: .45rem; margin-top: .9rem; }
.word-cloud span {
  padding: .32rem .58rem;
  border-radius: 999px;
  background: rgba(14, 165, 233, .09);
  color: #174069;
  font-family: "Lexend", "IBM Plex Sans KR", ui-sans-serif, system-ui, sans-serif;
  font-size: .9rem;
}
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: .8rem; }
.stat-card {
  padding: 1rem;
  border: 1px solid rgba(255,255,255,.82);
  border-radius: var(--radius-lg);
  background: rgba(255,255,255,.78);
  box-shadow: var(--shadow-soft);
}
.stat-card b { display: block; font-family: "Lexend", "IBM Plex Sans KR", sans-serif; font-size: 1.85rem; color: #0a2341; }
.stat-card span { color: #506985; font-weight: 600; }

@media (max-width: 760px) {
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .login-shell { grid-template-columns: 1fr; }
  .login-visual { min-height: auto; }
  .preview-card:nth-child(2) { margin-left: 0; }
}
@media (max-width: 560px) {
  .stats-grid { grid-template-columns: 1fr; }
  .topbar { align-items: flex-start; flex-direction: column; }
  nav { width: 100%; justify-content: flex-start; }
  .hero { grid-template-columns: 1fr; border-radius: 26px; }
  .progress-ring { min-width: 76px; width: 76px; height: 76px; }
  .actions { grid-template-columns: 1fr; }
  .card, .hero, .login-visual, .login-card { border-radius: 26px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}