/* ── reset ──────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }

/* ── colour tokens ──────────────────────────────────────────────────── */
:root {
  --bg:               #0b0f1c;
  --bg-card:          #131825;
  --bg-card-hover:    #192034;
  --bg-card-back:     #0d1220;
  --bg-input:         #111826;
  --bg-input-focus:   #131e30;
  --border:           #252d45;
  --divider:          #1e2640;
  --text:             #eef2f8;
  --text-dim:         #8a95b0;
  --text-dimmer:      #5a6480;
  --accent:           #185FA5;
  --accent-text:      #c8e2ff;
  --amber:            #f59e0b;
  --green:            #18a558;
  --red:              #c43d3d;
  --badge-bg:         #0e1e38;
  --badge-border:     #1e3a5c;
  --card-front-grad:       linear-gradient(145deg, #131825 0%, #1a2235 100%);
  --card-front-grad-hover: linear-gradient(145deg, #172032, #1f2a45);
  --breathe-color:    rgba(128,152,208,0.15);
}
html.light {
  --bg:               #f0f4fb;
  --bg-card:          #ffffff;
  --bg-card-hover:    #eef2fb;
  --bg-card-back:     #f8fafc;
  --bg-input:         #eef2fb;
  --bg-input-focus:   #e4ecf8;
  --border:           #d0d8eb;
  --divider:          #c8d4e8;
  --text:             #1a2035;
  --text-dim:         #5c6e8a;
  --text-dimmer:      #8a9ab8;
  --accent:           #185FA5;
  --accent-text:      #0c2d5a;
  --amber:            #b45309;
  --green:            #15803d;
  --red:              #b91c1c;
  --badge-bg:         #dbeafe;
  --badge-border:     #93c5fd;
  --card-front-grad:       linear-gradient(145deg, #edf2fb 0%, #e4ecf7 100%);
  --card-front-grad-hover: linear-gradient(145deg, #e0eaf7, #d8e4f2);
  --breathe-color:    rgba(24,95,165,0.18);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  transition: background .25s, color .25s;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; }

/* ── screens ────────────────────────────────────────────────────────── */
.screen { display: none !important; }
.screen.active { display: flex !important; }

/* ── theme toggle ───────────────────────────────────────────────────── */
#theme-toggle {
  position: fixed; top: 11px; right: 14px; z-index: 200;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 8px; width: 34px; height: 34px;
  font-size: 17px; cursor: pointer;
  display: grid; place-items: center;
  transition: background .2s, border-color .2s;
  line-height: 1;
}
#theme-toggle:hover { background: var(--bg-card-hover); border-color: var(--text-dim); }

/* ── IDLE SCREEN ────────────────────────────────────────────────────── */
#scn-idle {
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 2rem 1.25rem;
}
.idle-inner { width: 100%; max-width: 560px; text-align: center; }
.logo-badge {
  width: 72px; height: 72px; border-radius: 20px;
  background: #185FA5; color: #c8e2ff;
  font-size: 42px; font-weight: 700;
  display: grid; place-items: center;
  margin: 0 auto 1.5rem;
}
.idle-inner h1 {
  font-size: 2.25rem; font-weight: 700;
  letter-spacing: -0.5px; margin-bottom: 0.4rem;
}
.tagline { color: var(--text-dim); font-size: 1rem; margin-bottom: 2.5rem; }

.mode-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 0.875rem; }
.mode-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 16px; padding: 1.375rem 1.25rem;
  text-align: left; cursor: pointer; color: var(--text);
  transition: border-color .2s, background .2s;
}
.mode-card:hover { background: var(--bg-card-hover); border-color: var(--text-dim); }
.mode-card:active { transform: scale(0.98); }
.mode-icon { font-size: 1.75rem; margin-bottom: 0.625rem; }
.mode-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.35rem; }
.mode-card p { font-size: 0.85rem; color: var(--text-dim); line-height: 1.5; margin-bottom: 0.75rem; }
.scoring-hint {
  font-size: 0.75rem; color: var(--accent); font-weight: 600;
  border: 1px solid var(--badge-border); border-radius: 6px;
  padding: 4px 10px; display: inline-block;
  background: var(--badge-bg);
}
.leaderboard-note { margin-top: 2rem; font-size: 0.8rem; color: var(--text-dimmer); }

/* ── PIN gate ───────────────────────────────────────────────────────── */
#scn-pin {
  flex-direction: column; align-items: center; justify-content: center;
  min-height: 100vh; min-height: 100dvh; padding: 2rem 1.25rem;
}
#pin-form { display: flex; flex-direction: column; gap: 10px; width: 100%; max-width: 280px; margin: 0.25rem auto 0; }
.pin-input {
  width: 100%; text-align: center; letter-spacing: 0.4em;
  font-size: 1.4rem; font-weight: 700; font-family: inherit;
  padding: 13px 14px; border-radius: 12px;
  background: var(--bg-input); color: var(--text); border: 1.5px solid var(--border);
  outline: none; transition: border-color .2s, background .2s;
}
.pin-input:focus { border-color: var(--accent); background: var(--bg-input-focus); }
.pin-input.wrong { border-color: var(--red); animation: shake 0.38s ease; }
.pin-submit { width: 100%; margin: 0; }
.pin-msg { min-height: 1.2em; margin-top: 0.9rem; font-size: 0.9rem; color: var(--text-dim); }
.pin-msg.err { color: var(--red); font-weight: 600; }

/* ── GAME SCREEN ────────────────────────────────────────────────────── */
#scn-game {
  flex-direction: column;
  height: 100vh;
  height: 100dvh;            /* mobile: track the visible viewport so the answer bar stays put */
  overflow: hidden;
  padding: 0 1.5rem 1rem;
}

/* header */
#game-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.875rem 44px 0.75rem 0;   /* right pad keeps the streak clear of the fixed theme toggle */
  border-bottom: 1px solid var(--divider);
  flex-shrink: 0;
}
.hdr-left { display: flex; align-items: center; gap: 10px; }
.logo-sm {
  width: 30px; height: 30px; border-radius: 8px;
  background: #185FA5; color: #c8e2ff;
  display: grid; place-items: center;
  font-size: 17px; font-weight: 700;
  border: 0; padding: 0; font-family: inherit; cursor: pointer;
  transition: filter .15s, transform .1s;
}
.logo-sm:hover { filter: brightness(1.12); }
.logo-sm:active { transform: scale(0.93); }
.app-name {
  font-weight: 700; font-size: 15px; color: var(--text);
  letter-spacing: -0.2px; white-space: nowrap;
}
#mode-badge {
  font-size: 13px; color: var(--text-dim);
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 6px; padding: 3px 9px;
}
.hdr-stats { display: flex; gap: 1.25rem; align-items: center; }
.hdr-stat { text-align: center; }
.hdr-stat .val {
  display: block; font-size: 1.35rem; font-weight: 700; line-height: 1.1;
}
.hdr-stat .lbl {
  font-size: 11px; color: var(--text-dim);
  text-transform: uppercase; letter-spacing: 0.06em;
}
.hdr-stat.streak .val { color: var(--amber); }

/* progress bar */
#progress-bar-wrap { height: 3px; background: var(--divider); flex-shrink: 0; }
#progress-bar-fill { height: 100%; background: var(--accent); transition: width 0.4s ease; }

/* clue strip */
#clue-strip {
  display: flex; gap: 1.25rem; align-items: center;
  padding: 0.5rem 0;
  font-size: 0.95rem; color: var(--text-dim);
  border-bottom: 1px solid var(--divider);
  flex-shrink: 0;
}
.clue strong { color: var(--text); }
#fg-badge {
  margin-left: auto;
  font-size: 0.72rem; font-weight: 600;
  color: var(--accent);
  background: var(--badge-bg); border: 1px solid var(--badge-border);
  border-radius: 6px; padding: 2px 9px;
  display: none;
}

/* points indicator (cards mode) */
#points-row {
  display: flex; align-items: center; gap: 10px;
  padding: 0.4rem 0; flex-shrink: 0;
  font-size: 0.82rem; color: var(--text-dim);
  min-height: 28px;
}
.pt-dot {
  font-size: 1rem; color: var(--border);
  transition: color .25s, transform .25s;
}
.pt-dot.active { color: var(--amber); transform: scale(1.15); }

/* loading */
#loading-wrap {
  flex: 1; display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 1rem;
  color: var(--text-dim);
}
.loading-star { font-size: 3.5rem; color: var(--accent); animation: breathe 1.6s ease-in-out infinite; }
#loading-wrap p { font-size: 0.9rem; }

/* spectra grid */
#spectra-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  padding: 0.625rem 0 0;
  flex: 1;
  min-height: 0;
}

/* ── CARD FLIP ──────────────────────────────────────────────────────── */
.spec-card {
  perspective: 1000px;
  position: relative;
}
.card-inner {
  position: relative; width: 100%; height: 100%;
  transform-style: preserve-3d;
  transition: transform 0.55s cubic-bezier(0.4, 0.2, 0.2, 1);
}
.spec-card.flipped .card-inner { transform: rotateY(180deg); }
.spec-card.no-anim .card-inner { transition: none; }
.card-front, .card-back {
  position: absolute; inset: 0;
  border-radius: 14px;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  overflow: hidden;
}

/* front (face-down) */
.card-front {
  background: var(--card-front-grad);
  border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: border-color .2s, background .2s;
}
.card-front:hover { background: var(--card-front-grad-hover); border-color: var(--text-dim); }
.spec-card.flipped .card-front { pointer-events: none; }

/* back (spectrum visible) */
.card-back {
  background: var(--bg-card-back);
  border: 1px solid var(--border);
  transform: rotateY(180deg);
  display: flex; flex-direction: column;
}
.spec-tech-label {
  font-size: 13px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.08em; padding: 8px 12px 6px;
  border-bottom: 1px solid var(--divider); flex-shrink: 0;
  color: var(--text-dim);
}
.card-back.tech-ir  .spec-tech-label { color: #E8833A; }
.card-back.tech-ms  .spec-tech-label { color: #18a558; }
.card-back.tech-h1  .spec-tech-label { color: #8b80e8; }
.card-back.tech-c13 .spec-tech-label { color: #0E9BB5; }
.spec-svg-wrap {
  flex: 1; overflow: hidden; min-height: 0;
  display: flex; align-items: center; justify-content: center;
}
/* fill the whole card — the SVG viewBox preserves the chart's aspect ratio */
.spec-svg-wrap svg { width: 100%; height: 100%; display: block; }
.no-data-msg { color: var(--text-dimmer); padding: 1.5rem; font-size: 0.85rem; }

/* breathing icon on face-down cards */
.breathe-icon {
  font-size: 4.5rem; color: var(--breathe-color);
  animation: breathe 2.8s ease-in-out infinite;
  user-select: none; pointer-events: none;
}
@keyframes breathe {
  0%,100% { transform: scale(0.88); opacity: 0.3; }
  50%      { transform: scale(1.1);  opacity: 0.85; }
}

/* ── ANSWER AREA ────────────────────────────────────────────────────── */
#answer-area {
  padding: 0.625rem 0 0;
  border-top: 1px solid var(--divider);
  flex-shrink: 0;
}
.answer-row {
  display: flex; align-items: center; gap: 8px; margin-bottom: 7px;
}
.answer-row label {
  font-size: 14px; color: var(--text-dim); white-space: nowrap; flex-shrink: 0;
}
#answer-input {
  flex: 1;
  min-width: 0;            /* allow the field to shrink so Submit never gets clipped */
  padding: 10px 14px;
  background: var(--bg-input); color: var(--text);
  border: 1.5px solid var(--border); border-radius: 10px;
  font-size: 16px; font-family: inherit;
  outline: none; transition: border-color .2s, background .2s;
}
#answer-input:focus { border-color: var(--accent); background: var(--bg-input-focus); }
#answer-input:disabled { opacity: 0.4; cursor: not-allowed; }
#answer-input.wrong {
  border-color: var(--red);
  animation: shake 0.38s ease;
}
@keyframes shake {
  0%,100% { transform: translateX(0); }
  25%      { transform: translateX(-7px); }
  75%      { transform: translateX(7px); }
}
#btn-submit {
  background: var(--accent); color: #fff;
  border: none; border-radius: 10px;
  padding: 10px 20px; font-size: 15px; font-weight: 600;
  cursor: pointer; white-space: nowrap; flex-shrink: 0;
  transition: opacity .15s;
}
#btn-submit:hover:not(:disabled) { opacity: 0.85; }
#btn-submit:disabled { opacity: 0.4; cursor: not-allowed; }
.answer-actions { display: flex; gap: 7px; flex-wrap: wrap; }
.btn-sec {
  background: transparent; color: var(--text-dimmer);
  border: 1px solid var(--border); border-radius: 8px;
  padding: 7px 14px; font-size: 13px;
  cursor: pointer; transition: color .15s, border-color .15s;
}
.btn-sec:hover { color: var(--text); border-color: var(--text-dim); }
.btn-sec:disabled { opacity: 0.3; cursor: not-allowed; }

/* ── FEEDBACK PANEL ─────────────────────────────────────────────────── */
#feedback {
  flex-shrink: 0;
  padding: 0.75rem 0 0;
  border-top: 1px solid var(--divider);
}
.fb-correct, .fb-skip {
  display: flex; flex-direction: column; gap: 0.625rem;
}
.fb-top { display: flex; align-items: center; gap: 10px; }
.tick-circle {
  width: 26px; height: 26px; border-radius: 50%;
  background: var(--green); color: #fff;
  display: grid; place-items: center;
  font-size: 13px; font-weight: 700; flex-shrink: 0;
}
.pts-earned { font-size: 1rem; font-weight: 700; color: var(--amber); }
.streak-chip {
  font-size: 11px; font-weight: 600; color: var(--amber);
  background: rgba(245,158,11,.12); border: 1px solid rgba(245,158,11,.3);
  border-radius: 6px; padding: 2px 8px;
}
html.light .streak-chip {
  background: rgba(180,83,9,.1); border-color: rgba(180,83,9,.3);
}
.correct-iupac { font-size: 1.3rem; font-weight: 700; }
.fb-body { display: flex; align-items: center; gap: 1.25rem; flex-wrap: wrap; }
.struct-wrap {
  flex-shrink: 0;
  background: #fff; border-radius: 10px;
  padding: 4px;
  max-width: 220px; max-height: 140px; overflow: hidden;
}
.struct-wrap svg { width: 212px; height: 132px; display: block; }
.skip-label { font-size: 0.9rem; color: var(--text-dimmer); }
.skip-iupac { font-size: 1rem; font-weight: 600; color: var(--text-dim); }
.btn-next {
  align-self: flex-start; flex-shrink: 0;
  background: var(--accent); color: #fff;
  border: none; border-radius: 10px;
  padding: 10px 20px; font-size: 15px; font-weight: 600;
  cursor: pointer; transition: opacity .15s; margin-top: 2px;
}
.btn-next:hover { opacity: 0.85; }

/* ── SUMMARY SCREEN ─────────────────────────────────────────────────── */
#scn-summary {
  flex-direction: column;
  align-items: center; justify-content: center;
  min-height: 100vh; padding: 2rem 1.25rem;
}
.sum-inner { width: 100%; max-width: 420px; text-align: center; }
.sum-inner .logo-badge { margin-bottom: 1.25rem; }
.sum-inner h2 { font-size: 1.75rem; font-weight: 700; margin-bottom: 0.35rem; }
.sum-subtitle { color: var(--text-dim); font-size: 0.875rem; margin-bottom: 1.75rem; }
.sum-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 0.875rem;
  margin-bottom: 1.75rem;
}
.sum-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 14px; padding: 1.125rem;
}
.sum-card .s-val { font-size: 2rem; font-weight: 700; display: block; }
.sum-card .s-lbl {
  font-size: 11px; color: var(--text-dim);
  text-transform: uppercase; letter-spacing: 0.06em;
  margin-top: 3px; display: block;
}
.sum-card.highlight .s-val { color: var(--amber); }
.btn-again {
  display: block; width: 100%;
  background: var(--accent); color: #fff;
  border: none; border-radius: 12px;
  padding: 13px; font-size: 15px; font-weight: 600;
  cursor: pointer; margin-bottom: 0.625rem;
  transition: opacity .15s;
}
.btn-again:hover { opacity: 0.85; }
.btn-switch {
  display: block; width: 100%;
  background: transparent; color: var(--text-dim);
  border: 1px solid var(--border); border-radius: 12px;
  padding: 11px; font-size: 13px;
  cursor: pointer; transition: color .15s, border-color .15s;
}
.btn-switch:hover { color: var(--text); border-color: var(--text-dim); }

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

/* ── RESPONSIVE ─────────────────────────────────────────────────────── */
/* phones + portrait tablets: one spectrum wide, scroll through them vertically,
   while the answer bar stays pinned at the bottom of the screen */
@media (orientation: portrait), (max-width: 820px) {
  #spectra-grid {
    grid-template-columns: 1fr;
    grid-auto-rows: minmax(240px, 1fr);   /* each spectrum a usable height; scroll past the fold */
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }
}

@media (max-width: 600px) {
  .mode-cards { grid-template-columns: 1fr; }
  #spectra-grid { gap: 8px; }
  .hdr-stats { gap: 0.75rem; }
  .hdr-stat .val { font-size: 1rem; }
  #mode-badge { display: none; }               /* make room for the app name on phones */
  #scn-game { padding: 0 0.85rem 0.75rem; }    /* reclaim side margin for wider spectra */
}