/* ── RESET & BASE ────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

:root {
  /* Core palette */
  --bg: #08090f;
  --surface: #111320;
  --surface2: #181b2e;
  --surface3: #1e2238;
  --border: #252a45;
  --border2: #2f3558;

  /* Accent */
  --accent: #5b8af5;
  --accent2: #7c5bf7;
  --accent-glow: rgba(91, 138, 245, 0.22);
  --accent-glow2: rgba(124, 91, 247, 0.18);

  /* Status */
  --green: #22c55e;
  --green-bg: rgba(34, 197, 94, 0.10);
  --green-border: rgba(34, 197, 94, 0.30);
  --red: #f87171;
  --red-bg: rgba(248, 113, 113, 0.10);
  --red-border: rgba(248, 113, 113, 0.30);
  --yellow: #fbbf24;
  --yellow-bg: rgba(251, 191, 36, 0.12);

  /* Text */
  --text: #e8eaf6;
  --text2: #8b90b8;
  --text3: #5a6080;

  /* Geometry */
  --radius: 18px;
  --radius-sm: 12px;
  --radius-xs: 8px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
}

html {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  min-height: 100%;
}

body {
  min-height: 100vh;
  padding: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  background:
    radial-gradient(ellipse 90% 60% at 50% -10%, rgba(91,138,245,0.13), transparent),
    radial-gradient(ellipse 60% 40% at 90% 80%, rgba(124,91,247,0.09), transparent),
    var(--bg);
}

/* ── LAYOUT ──────────────────────────────────────────────── */
#app {
  width: 100%;
  max-width: 500px;
  padding: 16px 16px 56px;
  display: flex;
  flex-direction: column;
  gap: 0;
}

/* ── HEADER ──────────────────────────────────────────────── */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0 20px;
}

.app-title {
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.4px;
  background: linear-gradient(135deg, #e8eaf6, #8b90b8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.streak-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 50px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: background .2s, border-color .2s;
  backdrop-filter: blur(8px);
}

.streak-pill:hover { background: var(--surface3); border-color: var(--accent); }

/* ── HOME SCREEN ─────────────────────────────────────────── */
.home-hero {
  text-align: center;
  padding: 20px 0 28px;
}

.date-badge {
  display: inline-block;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 4px 16px;
  font-size: 12px;
  color: var(--text2);
  margin-bottom: 18px;
  letter-spacing: 0.3px;
}

.home-hero h1 {
  font-size: 32px;
  font-weight: 900;
  letter-spacing: -0.8px;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #fff 30%, var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.home-hero p { color: var(--text2); font-size: 15px; line-height: 1.5; }

/* Stats */
.stats-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 10px;
  margin-bottom: 20px;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 10px;
  text-align: center;
  transition: transform .2s, border-color .2s;
}

.stat-card:hover { transform: translateY(-2px); border-color: var(--border2); }
.stat-card .val { font-size: 28px; font-weight: 900; line-height: 1; letter-spacing: -0.5px; }
.stat-card .lbl { font-size: 11px; color: var(--text2); margin-top: 5px; text-transform: uppercase; letter-spacing: .6px; font-weight: 600; }
.stat-card.accent .val { color: var(--accent); }
.stat-card.green .val { color: var(--green); }
.stat-card.yellow .val { color: var(--yellow); }

/* Mode selector */
.mode-selector {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-bottom: 14px;
}

.mode-btn {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 12px;
  text-align: left;
  cursor: pointer;
  transition: border-color .2s, background .2s, transform .15s;
  -webkit-tap-highlight-color: transparent;
}

.mode-btn:hover { border-color: var(--accent); background: var(--surface2); }
.mode-btn:active { transform: scale(.97); }
.mode-btn.active {
  border-color: var(--accent);
  background: rgba(91,138,245,0.08);
  box-shadow: 0 0 0 1px var(--accent);
}
.mode-btn .mode-icon { font-size: 22px; margin-bottom: 6px; }
.mode-btn .mode-label { font-size: 13px; font-weight: 700; color: var(--text); }
.mode-btn .mode-desc { font-size: 11px; color: var(--text2); margin-top: 2px; line-height: 1.4; }

/* Count selector */
.count-selector {
  margin-bottom: 16px;
}
.count-label { font-size: 12px; font-weight: 700; color: var(--text2); text-transform: uppercase; letter-spacing: .6px; margin-bottom: 8px; }
.count-pills { display: flex; gap: 8px; flex-wrap: wrap; }
.count-pill {
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: 50px;
  padding: 6px 16px;
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: border-color .2s, background .2s;
  color: var(--text2);
}
.count-pill.active { border-color: var(--accent); background: rgba(91,138,245,0.12); color: var(--text); }

/* Start button */
.btn-start {
  width: 100%;
  padding: 18px;
  border-radius: var(--radius);
  border: none;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  font-size: 17px;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 4px 24px rgba(91,138,245,0.40), 0 0 0 0 rgba(91,138,245,0);
  transition: transform .15s, box-shadow .15s;
  letter-spacing: -0.2px;
  -webkit-tap-highlight-color: transparent;
  font-family: var(--font);
}

.btn-start:hover { box-shadow: 0 6px 32px rgba(91,138,245,0.55); }
.btn-start:active { transform: scale(.97); }

/* History */
.history-section { margin-top: 28px; }
.section-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--text3);
  text-transform: uppercase;
  letter-spacing: .9px;
  margin-bottom: 12px;
}

.history-bars { display: flex; gap: 6px; align-items: flex-end; height: 64px; }
.bar-wrap { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 4px; }
.bar {
  width: 100%;
  border-radius: 5px 5px 0 0;
  min-height: 4px;
  background: var(--surface2);
  border: 1px solid var(--border);
  transition: height .5s cubic-bezier(.34,1.56,.64,1);
}
.bar.filled { background: linear-gradient(to top, var(--accent), var(--accent2)); border-color: transparent; }
.bar.perfect { background: linear-gradient(to top, var(--green), #4ade80); border-color: transparent; }
.bar-day { font-size: 9px; color: var(--text3); text-transform: uppercase; font-weight: 600; }
.bar-score { font-size: 9px; font-weight: 700; color: var(--text2); }

/* Weak topics */
.weak-section { margin-top: 20px; }
.chip-row { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.chip {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 4px 12px;
  font-size: 11px;
  color: var(--text2);
  font-weight: 600;
  cursor: pointer;
  transition: background .2s, border-color .2s;
}
.chip:hover { border-color: var(--accent); background: var(--surface3); }
.chip.bad { border-color: var(--red-border); color: var(--red); background: var(--red-bg); }
.chip.bad:hover { background: rgba(248, 113, 113, 0.18); }

/* ── QUIZ SCREEN ─────────────────────────────────────────── */
.quiz-screen { display: flex; flex-direction: column; gap: 0; }

/* Progress */
.progress-header { display: flex; align-items: center; gap: 12px; margin-bottom: 20px; }
.progress-bar-wrap {
  flex: 1;
  height: 5px;
  background: var(--surface2);
  border-radius: 3px;
  overflow: hidden;
}
.progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 3px;
  transition: width .5s cubic-bezier(.34,1.56,.64,1);
}
.q-counter { font-size: 13px; color: var(--text2); white-space: nowrap; font-weight: 700; }

/* Question card */
.q-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  margin-bottom: 14px;
  animation: slide-in .3s cubic-bezier(.34,1.56,.64,1);
}

.q-card.shake {
  animation: shake 0.4s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
}

@keyframes shake {
  10%, 90% { transform: translate3d(-1px, 0, 0); }
  20%, 80% { transform: translate3d(2px, 0, 0); }
  30%, 50%, 70% { transform: translate3d(-4px, 0, 0); }
  40%, 60% { transform: translate3d(4px, 0, 0); }
}

@keyframes slide-in {
  from { opacity: 0; transform: translateY(16px) scale(.98); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

.topic-tag {
  font-size: 10px;
  color: var(--accent);
  background: var(--accent-glow);
  border-radius: 50px;
  padding: 3px 10px;
  display: inline-block;
  margin-bottom: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .5px;
  border: 1px solid rgba(91,138,245,0.2);
}

.q-text {
  font-size: 17px;
  font-weight: 700;
  line-height: 1.5;
  letter-spacing: -0.2px;
  margin-bottom: 2px;
}

/* Question image */
.q-image-wrap {
  margin: 14px 0 2px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--surface2);
}

.q-image-wrap img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius-sm);
  object-fit: cover;
  max-height: 260px;
}

/* Options */
.options { display: flex; flex-direction: column; gap: 10px; margin-top: 18px; }

.opt {
  display: flex;
  align-items: flex-start;
  gap: 13px;
  background: var(--surface2);
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 14px 15px;
  cursor: pointer;
  transition: border-color .15s, background .15s, transform .1s;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.opt:hover { border-color: var(--border2); background: var(--surface3); }
.opt:active { transform: scale(.985); }
.opt.selected { border-color: var(--accent); background: rgba(91,138,245,0.08); }
.opt.correct  { border-color: var(--green); background: var(--green-bg); }
.opt.wrong    { border-color: var(--red); background: var(--red-bg); }
.opt.dimmed   { opacity: .38; pointer-events: none; }

.opt-letter {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: var(--surface3);
  border: 1px solid var(--border2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 800;
  flex-shrink: 0;
  transition: background .15s, color .15s, border-color .15s;
}

.opt.selected .opt-letter { background: var(--accent); color: #fff; border-color: transparent; }
.opt.correct  .opt-letter { background: var(--green); color: #fff; border-color: transparent; }
.opt.wrong    .opt-letter { background: var(--red);   color: #fff; border-color: transparent; }
.opt-text { font-size: 15px; line-height: 1.45; padding-top: 3px; font-weight: 500; }

/* Feedback */
.feedback-box {
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  font-size: 14px;
  line-height: 1.55;
  animation: fade-in .25s ease;
  margin-bottom: 4px;
  font-weight: 500;
}

@keyframes fade-in { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: translateY(0); } }

.feedback-box.correct {
  background: var(--green-bg);
  border: 1px solid var(--green-border);
  color: #4ade80;
}
.feedback-box.wrong {
  background: var(--red-bg);
  border: 1px solid var(--red-border);
  color: #fca5a5;
}

.btn-next {
  width: 100%;
  padding: 16px;
  border-radius: var(--radius);
  border: none;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff;
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  margin-top: 14px;
  box-shadow: 0 4px 18px rgba(91,138,245,0.35);
  transition: transform .15s;
  font-family: var(--font);
}
.btn-next:active { transform: scale(.97); }

/* ── RESULTS SCREEN ──────────────────────────────────────── */
.results-screen { text-align: center; padding: 10px 0; animation: slide-in .35s cubic-bezier(.34,1.56,.64,1); }

.results-emoji { font-size: 64px; margin-bottom: 10px; animation: bounce .6s cubic-bezier(.34,1.56,.64,1) .1s both; }
@keyframes bounce { from { transform: scale(0.5); opacity: 0; } to { transform: scale(1); opacity: 1; } }

.results-title { font-size: 28px; font-weight: 900; letter-spacing: -0.6px; margin-bottom: 5px; }
.results-sub { color: var(--text2); font-size: 14px; margin-bottom: 28px; font-weight: 500; }

.score-circle {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  margin: 0 auto 28px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 3px solid var(--accent);
  background: radial-gradient(circle, rgba(91,138,245,0.10), var(--surface));
  box-shadow: 0 0 40px rgba(91,138,245,0.2);
  animation: bounce .6s cubic-bezier(.34,1.56,.64,1) .2s both;
}

.score-circle .big { font-size: 42px; font-weight: 900; line-height: 1; letter-spacing: -1px; }
.score-circle .small { font-size: 13px; color: var(--text2); margin-top: 3px; font-weight: 600; }
.score-circle.perfect { border-color: var(--green); box-shadow: 0 0 40px rgba(34,197,94,0.25); background: radial-gradient(circle, rgba(34,197,94,0.10), var(--surface)); }
.score-circle.perfect .big { color: var(--green); }

.streak-reward {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  padding: 16px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 14px;
  text-align: left;
}

.streak-reward .icon { font-size: 30px; }
.streak-reward .msg { font-size: 14px; line-height: 1.45; font-weight: 500; }
.streak-reward .msg strong { color: var(--yellow); }

/* Breakdown */
.breakdown { text-align: left; margin-bottom: 24px; }
.breakdown-item {
  display: flex;
  flex-direction: column;
  padding: 11px 0;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s;
}
.breakdown-item:hover { background: rgba(255,255,255,0.02); }
.breakdown-item:last-child { border-bottom: none; }
.bd-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}
.bd-left { display: flex; align-items: center; gap: 10px; flex: 1; }
.bd-dot { width: 8px; height: 8px; border-radius: 50%; flex-shrink: 0; }
.bd-dot.g { background: var(--green); }
.bd-dot.r { background: var(--red); }
.bd-title-wrap { flex: 1; padding-right: 15px; }
.bd-label { color: var(--text2); font-size: 11px; margin-top: 2px; font-weight: 600; }

.bd-details {
  display: none;
  margin-top: 12px;
  padding: 12px;
  background: var(--surface2);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border2);
  font-size: 13px;
  line-height: 1.5;
  animation: fade-in 0.2s ease;
}
.bd-details.open { display: block; }
.bd-full-q { margin-bottom: 10px; font-weight: 700; color: var(--text); }
.bd-opts { margin-bottom: 10px; display: flex; flex-direction: column; gap: 4px; }
.bd-opt { padding: 6px 10px; border-radius: 6px; background: var(--surface3); font-size: 12px; }
.bd-opt.correct { background: var(--green-bg); color: #4ade80; border: 1px solid var(--green-border); }
.bd-opt.wrong { background: var(--red-bg); color: #fca5a5; border: 1px solid var(--red-border); }
.bd-exp { color: var(--text2); font-size: 12px; }

.btn-retake {
  padding: 12px 20px;
  border-radius: var(--radius-xs);
  border: 1.5px solid var(--border2);
  background: var(--surface2);
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: background .15s, border-color .2s;
  font-family: var(--font);
}
.btn-retake:hover { background: var(--surface3); border-color: var(--accent); }

.btn-home {
  width: 100%;
  padding: 16px;
  border-radius: var(--radius);
  border: 1.5px solid var(--border2);
  background: var(--surface2);
  color: var(--text);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: background .15s, border-color .2s;
  font-family: var(--font);
}
.btn-home:hover { background: var(--surface3); border-color: var(--accent); }

/* ── UTILS ───────────────────────────────────────────────── */
.hidden { display: none !important; }