:root {
  --navy: #14213d;
  --navy-2: #1d2f55;
  --ink: #20242c;
  --muted: #5f6673;
  --line: #e3e6ec;
  --bg: #f6f7f9;
  --card: #ffffff;
  --accent: #d3122e;        /* Collins-style crimson */
  --accent-dark: #ab0d24;
  --blue: #2456c4;          /* Longman-style blue */
  --blue-soft: #e9effc;
  --gold: #f4b942;
  --green: #1f8a4c;
  --green-soft: #e7f5ec;
  --red-soft: #fdecee;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(16, 24, 48, 0.07), 0 6px 18px rgba(16, 24, 48, 0.05);
  --serif: "Source Serif 4", Georgia, serif;
  --sans: "Inter", "Segoe UI", "Apple SD Gothic Neo", system-ui, sans-serif;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: var(--sans);
  background: var(--bg);
  color: var(--ink);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.hidden { display: none !important; }
a { color: var(--blue); }

/* ================= masthead ================= */
.masthead {
  background: var(--navy);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 20;
  box-shadow: 0 2px 12px rgba(10, 16, 35, 0.35);
}
.masthead-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
  height: 64px;
  display: flex;
  align-items: center;
  gap: 28px;
}
.brand { display: flex; align-items: center; gap: 11px; text-decoration: none; color: #fff; }
.brand-logo {
  width: 38px; height: 38px;
  background: var(--accent);
  border-radius: 9px;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -1px;
  box-shadow: inset 0 -2px 0 rgba(0,0,0,0.18);
}
.brand-logo-x { color: var(--gold); }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-weight: 800; font-size: 1.05rem; letter-spacing: 0.01em; }
.brand-by { font-weight: 500; font-size: 0.72rem; color: #9fb0d4; margin-left: 4px; }
.brand-sub { font-size: 0.67rem; color: #9fb0d4; letter-spacing: 0.06em; text-transform: uppercase; }

.main-nav { display: flex; gap: 4px; flex: 1; }
.nav-link {
  background: none;
  border: none;
  color: #c3cde4;
  font: 600 0.9rem var(--sans);
  padding: 8px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.nav-link:hover { color: #fff; background: rgba(255,255,255,0.08); }
.nav-link.active { color: #fff; background: rgba(255,255,255,0.14); }
.nav-count {
  background: var(--gold);
  color: var(--navy);
  border-radius: 999px;
  font-size: 0.7rem;
  padding: 1px 7px;
  margin-left: 3px;
  font-weight: 700;
}

.masthead-right { display: flex; align-items: center; gap: 10px; }
.level-badge {
  background: var(--gold);
  color: var(--navy);
  border: none;
  font: 700 0.8rem var(--sans);
  padding: 5px 13px;
  border-radius: 999px;
  cursor: pointer;
}
.level-badge:hover { filter: brightness(1.06); }
.icon-btn {
  background: none;
  border: none;
  color: #c3cde4;
  cursor: pointer;
  padding: 7px;
  border-radius: 8px;
  display: flex;
}
.icon-btn:hover { color: #fff; background: rgba(255,255,255,0.08); }

/* ================= layout ================= */
main { max-width: 1080px; margin: 0 auto; padding: 32px 20px 64px; }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 26px;
}
.eyebrow {
  color: var(--accent);
  font-weight: 700;
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin: 0 0 8px;
}
h1 { font-family: var(--serif); font-weight: 700; font-size: 1.9rem; margin: 0 0 10px; line-height: 1.25; }
.lede { color: var(--muted); font-size: 1.02rem; margin-top: 0; }
.hint { color: var(--muted); font-size: 0.83rem; }
.btn-row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 8px; }

/* ================= buttons & fields ================= */
.btn {
  display: inline-block;
  border: 1px solid #cdd3de;
  background: #fff;
  color: var(--ink);
  border-radius: 9px;
  padding: 10px 18px;
  font: 600 0.92rem var(--sans);
  cursor: pointer;
  transition: background 0.15s, transform 0.05s, box-shadow 0.15s;
}
.btn:hover { background: #f2f4f8; }
.btn:active { transform: translateY(1px); }
.btn.lg { padding: 13px 26px; font-size: 1rem; }
.btn.primary {
  background: var(--navy);
  border-color: var(--navy);
  color: #fff;
}
.btn.primary:hover { background: var(--navy-2); }
.btn.accent {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.btn.accent:hover { background: var(--accent-dark); }
.btn.ghost { border: none; background: none; color: var(--blue); }
.btn:disabled { opacity: 0.55; cursor: not-allowed; }

.field { margin: 16px 0; }
.field label { display: block; font-weight: 600; font-size: 0.84rem; margin-bottom: 6px; }
.field input, .field select {
  width: 100%;
  padding: 11px 13px;
  border: 1px solid #cdd3de;
  border-radius: 9px;
  font: 400 0.95rem var(--sans);
  background: #fff;
}
.field input:focus, .field select:focus,
.search-form input:focus, .try-form input:focus {
  outline: 3px solid var(--blue-soft);
  border-color: var(--blue);
}

/* ================= onboarding ================= */
.onboard {
  max-width: 620px;
  margin: 40px auto;
  padding: 42px 44px;
}
.onboard h1 { font-size: 2.1rem; }

/* ================= level test ================= */
.level-picker { margin-top: 18px; }
.level-options { display: flex; gap: 8px; flex-wrap: wrap; }
.level-opt { min-width: 58px; font-weight: 700; }
.level-opt:hover { border-color: var(--navy); }

.quiz-progress {
  height: 7px;
  background: var(--blue-soft);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 12px;
}
.quiz-bar { height: 100%; width: 0; background: var(--blue); transition: width 0.3s; }
.quiz-counter { color: var(--muted); font-size: 0.82rem; margin: 0 0 4px; font-weight: 600; letter-spacing: 0.03em; }
.quiz-question { font-family: var(--serif); font-size: 1.35rem; margin: 6px 0 4px; }
.quiz-options { display: flex; flex-direction: column; gap: 10px; margin-top: 18px; }
.quiz-opt { text-align: left; font-size: 1rem; font-weight: 500; }
.quiz-opt.correct { background: var(--green-soft); border-color: var(--green); color: var(--green); font-weight: 700; }
.quiz-opt.wrong { background: var(--red-soft); border-color: var(--accent); color: var(--accent); }
.result-level { color: var(--accent); }

/* ================= dictionary hero ================= */
.hero { text-align: center; padding: 26px 0 34px; }
.hero-title { font-size: 2rem; margin-bottom: 22px; }
.search-form {
  position: relative;
  display: flex;
  gap: 10px;
  max-width: 640px;
  margin: 0 auto;
}
.search-icon {
  position: absolute;
  left: 16px; top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  pointer-events: none;
}
.search-form input {
  flex: 1;
  padding: 14px 16px 14px 46px;
  font: 400 1.08rem var(--sans);
  border: 1.5px solid #cdd3de;
  border-radius: 11px;
  box-shadow: var(--shadow);
}
.hero-sub { color: var(--muted); font-size: 0.88rem; margin-top: 14px; }

/* ================= loading / error ================= */
.loading { display: flex; align-items: center; gap: 14px; max-width: 640px; margin: 0 auto; }
.spinner {
  width: 26px; height: 26px;
  border: 3px solid var(--blue-soft);
  border-top-color: var(--blue);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  flex-shrink: 0;
}
.spinner.small { width: 20px; height: 20px; }
@keyframes spin { to { transform: rotate(360deg); } }
.error { border-left: 4px solid var(--accent); color: var(--accent-dark); max-width: 640px; margin: 0 auto; }

/* ================= entry ================= */
.entry {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 22px;
  align-items: start;
}
@media (max-width: 820px) { .entry { grid-template-columns: 1fr; } }
.entry-main { padding: 30px 34px; }

.entry-head {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  border-bottom: 2px solid var(--line);
  padding-bottom: 16px;
  margin-bottom: 18px;
}
.headword {
  font-family: var(--serif);
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0;
  line-height: 1.1;
}
.speak-btn {
  background: var(--blue-soft);
  color: var(--blue);
  border: none;
  border-radius: 50%;
  width: 34px; height: 34px;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
}
.speak-btn:hover { background: #d7e2fa; }
.entry-pron { color: var(--muted); font-size: 1.05rem; }
.pos-badge {
  background: var(--navy);
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 5px;
}
.freq-dots { color: var(--green); font-size: 0.78rem; font-weight: 700; letter-spacing: 0.04em; }

.defs ol { padding-left: 26px; margin: 0; }
.defs li { margin-bottom: 16px; padding-left: 4px; }
.defs li::marker { color: var(--accent); font-weight: 700; font-family: var(--serif); }
.def-sense { margin: 0; font-size: 1.02rem; }
.def-example {
  margin: 5px 0 0;
  color: var(--blue);
  font-family: var(--serif);
  font-style: italic;
  font-size: 0.98rem;
}
.def-example::before { content: "“"; }
.def-example::after { content: "”"; }
.speak-mini {
  background: none; border: none; cursor: pointer;
  color: var(--muted); font-size: 0.85rem; padding: 0 4px;
}
.speak-mini:hover { color: var(--blue); }

.usage-tip {
  background: #fdf7e8;
  border: 1px solid #f0dfae;
  border-radius: 10px;
  padding: 12px 16px;
  margin: 4px 0 18px;
}
.usage-tip-label { font-weight: 700; font-size: 0.78rem; color: #9a7411; letter-spacing: 0.05em; text-transform: uppercase; }
.usage-tip p { margin: 4px 0 0; font-size: 0.95rem; }

.entry-section { margin-top: 24px; }
.section-title {
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--navy);
  border-bottom: 2px solid var(--line);
  padding-bottom: 6px;
  margin: 0 0 12px;
  font-weight: 800;
}

.chip-row { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  border: 1px solid var(--line);
  background: var(--bg);
  border-radius: 999px;
  padding: 4px 14px;
  font-size: 0.9rem;
  cursor: pointer;
}
.chip:hover { border-color: var(--blue); color: var(--blue); }
.chip .chip-pos { color: var(--muted); font-style: italic; font-size: 0.78rem; margin-left: 5px; }

.colloc-list { list-style: none; padding: 0; margin: 0; }
.colloc-list li { margin-bottom: 9px; font-size: 0.97rem; }
.colloc-phrase { font-weight: 700; color: var(--navy); }
.colloc-ex { color: var(--muted); font-style: italic; font-family: var(--serif); }

.syn-list { list-style: none; padding: 0; margin: 0; }
.syn-list li { margin-bottom: 10px; }
.syn-word {
  border: none;
  background: var(--blue-soft);
  color: var(--blue);
  font: 700 0.93rem var(--sans);
  padding: 3px 12px;
  border-radius: 7px;
  cursor: pointer;
}
.syn-word:hover { background: #d7e2fa; }
.syn-note { color: var(--muted); font-size: 0.93rem; }

/* try it yourself */
.try-box {
  background: linear-gradient(180deg, #f8faff, #f1f5fd);
  border: 1px solid #dbe4f5;
  border-radius: 10px;
  padding: 18px 20px;
}
.try-box .section-title { border-bottom-color: #dbe4f5; }
.try-lede { margin: 0 0 12px; font-size: 0.93rem; color: var(--muted); }
.try-form { display: flex; gap: 10px; flex-wrap: wrap; }
.try-form input {
  flex: 1;
  min-width: 220px;
  padding: 11px 14px;
  border: 1px solid #cdd3de;
  border-radius: 9px;
  font: 400 0.95rem var(--sans);
}
.try-feedback {
  margin-top: 14px;
  border-radius: 9px;
  padding: 13px 16px;
  font-size: 0.94rem;
  background: #fff;
  border: 1px solid var(--line);
}
.try-feedback.good { border-color: var(--green); background: var(--green-soft); }
.try-feedback.fix { border-color: var(--gold); background: #fdf7e8; }
.try-feedback .fb-title { font-weight: 800; display: block; margin-bottom: 4px; }
.try-feedback .fb-better { margin-top: 6px; font-family: var(--serif); font-style: italic; color: var(--navy); }

/* entry sidebar */
.entry-side { display: flex; flex-direction: column; gap: 14px; }
.entry-figure { margin: 0; padding: 14px; }
.image-box {
  width: 100%;
  aspect-ratio: 1 / 1;
  background: var(--bg);
  border-radius: 9px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
.image-box img { width: 100%; height: 100%; object-fit: cover; }
.image-fail { font-size: 2rem; opacity: 0.5; }
.entry-figure figcaption { margin-top: 9px; color: var(--muted); font-size: 0.78rem; text-align: center; }
.saved-note { padding: 12px 16px; font-size: 0.85rem; color: var(--green); font-weight: 600; }
.linklike { background: none; border: none; padding: 0; color: var(--blue); font: inherit; cursor: pointer; text-decoration: underline; }

/* ================= wordbook ================= */
.tab-head { margin-bottom: 22px; }
.wordbook-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
}
.word-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 16px 18px;
  cursor: pointer;
  position: relative;
  transition: transform 0.12s, box-shadow 0.12s;
}
.word-card:hover { transform: translateY(-2px); box-shadow: 0 4px 14px rgba(16,24,48,0.12); }
.word-card h3 { font-family: var(--serif); color: var(--accent); margin: 0 0 2px; font-size: 1.25rem; }
.word-card .wc-pos { color: var(--muted); font-style: italic; font-size: 0.78rem; }
.word-card .wc-sense {
  font-size: 0.85rem;
  color: var(--muted);
  margin: 6px 0 0;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.wc-remove {
  position: absolute;
  top: 8px; right: 10px;
  background: none; border: none;
  color: #b6bcc8;
  font-size: 1rem;
  cursor: pointer;
  padding: 2px 6px;
}
.wc-remove:hover { color: var(--accent); }

.empty-state { text-align: center; padding: 48px 26px; max-width: 560px; margin: 0 auto; }
.empty-emoji { font-size: 2.4rem; margin: 0 0 8px; }

/* ================= practice ================= */
#practice-quiz { max-width: 680px; margin: 0 auto; padding: 30px 34px; }
.pq-explain {
  margin-top: 16px;
  background: var(--blue-soft);
  border-radius: 9px;
  padding: 12px 16px;
  font-size: 0.93rem;
}
#pq-next { margin-top: 14px; }
#practice-result h2 { font-family: var(--serif); font-size: 2rem; margin: 6px 0; }

/* ================= footer ================= */
.site-footer {
  border-top: 1px solid var(--line);
  background: #fff;
  text-align: center;
  color: var(--muted);
  font-size: 0.78rem;
  padding: 18px;
}
.site-footer p { margin: 0; }
.site-footer p + p { margin-top: 4px; }

/* ================= modal ================= */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(12, 18, 38, 0.5);
  backdrop-filter: blur(2px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 50;
}
.modal { width: min(460px, 92vw); max-height: 88vh; overflow-y: auto; }
.modal h2 { margin-top: 0; font-family: var(--serif); }
.modal-actions { display: flex; justify-content: space-between; margin-top: 20px; }

@media (max-width: 720px) {
  .brand-sub { display: none; }
  .masthead-inner { gap: 14px; }
  .hero-title { font-size: 1.5rem; }
  .onboard { padding: 30px 24px; }
  .entry-main { padding: 22px; }
}