:root {
  --navy: #0b1f3a;
  --navy-2: #123056;
  --green: #0f6b4c;
  --green-2: #14805c;
  --gold: #d4a017;
  --gold-2: #f0c14b;
  --cream: #f6f1e6;
  --paper: #fffdf8;
  --ink: #1a1f2b;
  --muted: #5b6578;
  --line: #e4dccb;
  --danger: #b42318;
  --ok: #107a4b;
  --card: #ffffff;
  --shadow: 0 10px 30px rgba(11, 31, 58, 0.12);
  --radius: 16px;
  --font: "Source Serif 4", Georgia, serif;
  --sans: "Manrope", "Segoe UI", sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--cream);
  color: var(--ink);
  min-height: 100vh;
  line-height: 1.55;
}

.app-bg {
  position: fixed; inset: 0; z-index: -1;
  background:
    radial-gradient(900px 400px at 10% -10%, rgba(15,107,76,.18), transparent 60%),
    radial-gradient(700px 400px at 100% 0%, rgba(212,160,23,.16), transparent 55%),
    linear-gradient(180deg, #f8f3e8 0%, #efe6d4 100%);
}

header.top {
  position: sticky; top: 0; z-index: 40;
  background: linear-gradient(90deg, var(--navy) 0%, var(--navy-2) 55%, #0d4a36 100%);
  color: #fff;
  box-shadow: 0 4px 20px rgba(0,0,0,.25);
}
.top-inner {
  max-width: 1200px; margin: 0 auto;
  padding: 14px 20px 10px;
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
}
.brand { display: flex; align-items: center; gap: 12px; min-width: 220px; }
.logo {
  width: 46px; height: 46px; border-radius: 12px;
  background: linear-gradient(145deg, var(--gold), #8a6a10);
  color: var(--navy);
  display: grid; place-items: center;
  font-weight: 800; font-size: 14px; letter-spacing: .04em;
  box-shadow: inset 0 0 0 2px rgba(255,255,255,.25);
}
.brand h1 { font-size: 1.25rem; font-weight: 800; letter-spacing: .08em; }
.brand p { font-size: .72rem; opacity: .82; font-weight: 500; }
.update-chip {
  margin-left: auto;
  background: rgba(255,255,255,.1);
  border: 1px solid rgba(240,193,75,.45);
  color: var(--gold-2);
  font-size: .72rem;
  padding: 6px 10px; border-radius: 999px;
  white-space: nowrap;
}
nav.tabs {
  width: 100%;
  display: flex; gap: 6px; overflow-x: auto; padding: 4px 0 8px;
}
nav.tabs button {
  border: 0; background: transparent; color: #d7deea;
  padding: 8px 12px; border-radius: 10px; cursor: pointer;
  font-family: var(--sans); font-size: .85rem; font-weight: 600; white-space: nowrap;
}
nav.tabs button:hover, nav.tabs button.active {
  background: rgba(255,255,255,.12); color: #fff;
}
nav.tabs button.active { box-shadow: inset 0 -2px 0 var(--gold); }

main { max-width: 1200px; margin: 0 auto; padding: 22px 20px 80px; }
.view { display: none; }
.view.active { display: block; animation: fade .25s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.hero {
  display: grid; grid-template-columns: 1.4fr .8fr; gap: 18px; margin-bottom: 22px;
}
.hero-card, .panel, .article, .q-card, .term-card, .flash {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.hero-card { padding: 28px 28px 24px; }
.hero-card h2 {
  font-family: var(--font);
  font-size: 2rem; line-height: 1.2; color: var(--navy);
  margin: 8px 0 12px;
}
.kicker {
  color: var(--green); font-weight: 700; font-size: .78rem; letter-spacing: .12em; text-transform: uppercase;
}
.hero-card p.lead { color: var(--muted); max-width: 62ch; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-top: 18px; }
.stat {
  background: linear-gradient(180deg, #fbf7ee, #f3ead6);
  border-radius: 12px; padding: 12px; text-align: center;
}
.stat b { display: block; font-size: 1.35rem; color: var(--navy); }
.stat span { font-size: .75rem; color: var(--muted); }
.side-card { padding: 20px; }
.side-card h3 { font-size: 1rem; margin-bottom: 10px; color: var(--navy); }
.side-card ol { padding-left: 18px; color: var(--muted); font-size: .9rem; }
.side-card li { margin: 6px 0; }

.search-row { display: flex; gap: 8px; margin: 16px 0 8px; }
.search-row input, select, .field {
  flex: 1; border: 1px solid var(--line); border-radius: 12px;
  padding: 11px 14px; font: inherit; background: #fff;
}
.btn {
  border: 0; border-radius: 12px; padding: 11px 16px; cursor: pointer;
  font-family: var(--sans); font-weight: 700; font-size: .9rem;
}
.btn-gold { background: var(--gold); color: var(--navy); }
.btn-navy { background: var(--navy); color: #fff; }
.btn-green { background: var(--green); color: #fff; }
.btn-ghost { background: #fff; border: 1px solid var(--line); color: var(--ink); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; margin-top: 16px; }
.tile {
  background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px;
  cursor: pointer; transition: transform .15s, box-shadow .15s;
}
.tile:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.tile h3 { font-size: 1rem; margin-bottom: 6px; color: var(--navy); }
.tile p { font-size: .82rem; color: var(--muted); }

.toolbar {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 14px;
}
.chip {
  font-size: .75rem; padding: 5px 10px; border-radius: 999px;
  background: #eef6f1; color: var(--green); font-weight: 700;
}
.chip.hot { background: #fff3d6; color: #8a5a00; }
.chip.ms { background: #e8eef9; color: #1d3b78; }

.article { padding: 18px 20px; margin-bottom: 12px; }
.article h3 { font-family: var(--font); color: var(--navy); font-size: 1.15rem; }
.meta { display: flex; gap: 6px; flex-wrap: wrap; margin: 8px 0; }
.art-text { white-space: pre-wrap; font-size: .95rem; color: #2a3140; }
.explain, .msnote {
  margin-top: 12px; padding: 12px 14px; border-radius: 12px; font-size: .9rem;
}
.explain { background: #f4faf6; border-left: 4px solid var(--green); }
.msnote { background: #fff8e8; border-left: 4px solid var(--gold); }
.art-actions { display: flex; gap: 8px; margin-top: 12px; }

.flash-wrap { max-width: 640px; margin: 20px auto; }
.flash {
  min-height: 280px; padding: 28px; display: grid; place-items: center; text-align: center;
  cursor: pointer; position: relative;
}
.flash .side { font-size: .75rem; letter-spacing: .14em; text-transform: uppercase; color: var(--gold); margin-bottom: 10px; }
.flash h3 { font-family: var(--font); font-size: 1.45rem; color: var(--navy); }
.flash p { margin-top: 10px; color: var(--muted); }
.progress-bar { height: 8px; background: #e8e0d0; border-radius: 99px; overflow: hidden; margin: 12px 0; }
.progress-bar span { display: block; height: 100%; background: linear-gradient(90deg, var(--green), var(--gold)); }

.q-card { padding: 22px; }
.q-card h3 { font-family: var(--font); color: var(--navy); margin-bottom: 14px; }
.options { display: grid; gap: 8px; }
.opt {
  border: 1px solid var(--line); background: #fff; border-radius: 12px;
  padding: 12px 14px; text-align: left; cursor: pointer; font: inherit;
}
.opt:hover { border-color: var(--green); }
.opt.correct { background: #e7f6ee; border-color: var(--ok); }
.opt.wrong { background: #fdecea; border-color: var(--danger); }
.feedback { margin-top: 12px; font-size: .92rem; }
.score { font-weight: 800; color: var(--navy); }

.term-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.term-card { padding: 16px; }
.term-card h3 { color: var(--navy); font-size: 1.02rem; }
.term-card .art { font-size: .75rem; color: var(--green); font-weight: 700; margin: 4px 0 8px; }

.ms-block { padding: 20px; margin-bottom: 14px; }
.ms-block h3 { color: var(--navy); margin-bottom: 8px; }
.ms-block ul { padding-left: 18px; color: #334; }
.ms-block li { margin: 6px 0; }

footer {
  text-align: center; color: var(--muted); font-size: .78rem; padding: 10px 16px 28px;
}

.tts-bar {
  position: sticky; bottom: 12px; z-index: 20;
  max-width: 1200px; margin: 0 auto;
  background: var(--navy); color: #fff;
  border-radius: 14px; padding: 10px 14px;
  display: none; align-items: center; gap: 10px;
  box-shadow: var(--shadow);
}
.tts-bar.on { display: flex; }
.tts-bar span { font-size: .8rem; flex: 1; opacity: .9; }

@media (max-width: 860px) {
  .hero, .grid-3, .term-grid { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr 1fr 1fr; }
  .update-chip { margin-left: 0; }
  .hero-card h2 { font-size: 1.55rem; }
}