/*
  ============================================================
  shared/drill_preview.css
  © 2026 Alondra Delgado. All rights reserved. Part of MVP Algebra 1.

  The drill's own component styles, extracted VERBATIM from drill.html so the
  three-problem preview on /students is not a lookalike of the product -- it is
  the product's actual interface. A student taps through the preview, makes an
  account, and meets the same screen again. That is the point: the sneak peek
  has to BE the thing.

  "Refactoring is a MOVE, not a REDESIGN" (CLAUDE.md 12.2). Not one value here
  was changed -- rules were selected, not rewritten. Media queries are carried
  across with their rules, so the mobile layout stays mobile-only.

  IF YOU RESTYLE ANY OF THESE IN drill.html, RESTYLE THEM HERE TOO. Two copies
  on purpose -- drill.html keeps its own so it gains no runtime dependency --
  and they are meant to be identical:
    .drill-header .drill-counter .drill-stats .diff-badge .drill-stat
    .progress-track .progress-fill .question-card .question-text
    .question-graph .options .option .option-letter .option-text .btn

  Requires shared/theme_engine.css for the variables it refers to.
  ============================================================
*/
.btn { font-family: 'Bungee', cursive; font-size: 1.15rem; padding: 18px 44px; background: linear-gradient(135deg, var(--cyan), var(--primary-deep)); color: #000; border: none; border-radius: 14px; cursor: pointer; letter-spacing: 0.1em; box-shadow: 0 6px 0 var(--primary-darker), 0 10px 24px var(--cyan-glow); transition: transform 0.15s, box-shadow 0.15s; text-transform: uppercase; }
.btn:hover { transform: translateY(-2px); box-shadow: 0 8px 0 var(--primary-darker), 0 14px 32px var(--cyan-glow); }
.btn:active { transform: translateY(3px); box-shadow: 0 3px 0 var(--primary-darker); }
.drill-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 22px; flex-wrap: wrap; gap: 12px; }
.drill-counter { font-family: 'JetBrains Mono', monospace; font-size: 1.3rem; font-weight: 700; color: var(--text); }
.drill-counter .num { color: var(--cyan); font-size: 1.5rem; }
.drill-stats { display: flex; gap: 20px; align-items: center; }
.drill-stat { display: flex; align-items: center; gap: 6px; font-family: 'JetBrains Mono', monospace; font-size: 1rem; font-weight: 700; }
.drill-stat.streak { color: var(--gold); }
.drill-stat.time { color: var(--cyan); }
.drill-stat .label { color: var(--text-dim); font-size: 0.75rem; letter-spacing: 0.1em; }
.diff-badge { font-family: 'Bungee', cursive; padding: 5px 12px; border-radius: 8px; font-size: 0.7rem; letter-spacing: 0.15em; }
.diff-badge.easy { background: rgba(57, 255, 20, 0.15); color: var(--green); border: 1px solid var(--green); }
.diff-badge.medium { background: rgba(0, 229, 255, 0.15); color: var(--cyan); border: 1px solid var(--cyan); }
.diff-badge.hard { background: rgba(255, 45, 149, 0.15); color: var(--pink); border: 1px solid var(--pink); }
.progress-track { height: 6px; background: rgba(255, 255, 255, 0.08); width: 100%; border-radius: 3px; margin-bottom: 24px; overflow: hidden; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--cyan), var(--pink)); box-shadow: 0 0 10px var(--cyan-glow); transition: width 0.5s cubic-bezier(0.4, 0, 0.2, 1); width: 0%; }
.question-card { background: var(--panel); border: 2px solid var(--panel-border); border-radius: 22px; padding: 36px 44px; backdrop-filter: blur(10px); margin-bottom: 24px; display: grid; grid-template-columns: 1fr; grid-template-rows: auto auto; gap: 24px; }
.question-text { font-size: clamp(1.5rem, 2.2vw, 1.95rem); font-weight: 700; line-height: 1.4; color: var(--text); text-align: center; margin-bottom: 24px; }
.question-text .eq, .question-text .var { font-family: 'JetBrains Mono', monospace; color: var(--cyan); font-weight: 700; font-style: normal; }
.question-text .block-eq { display: block; text-align: center; font-family: 'STIX Two Text', 'Cambria Math', 'Times New Roman', serif; font-weight: 500; font-size: 1.3em; margin: 14px 0; color: var(--cyan); }
.question-graph { display: flex; justify-content: center; margin: 16px 0; }
.question-graph svg, .question-graph table { max-width: 100%; height: auto; }
.options { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.option { display: flex; align-items: center; gap: 16px; padding: 18px 22px; border: 2px solid var(--panel-border); border-radius: 14px; background: rgba(255, 255, 255, 0.02); font-size: clamp(1.05rem, 1.4vw, 1.2rem); font-weight: 600; transition: all 0.2s; cursor: pointer; position: relative; }
.option:hover:not(.disabled) { border-color: var(--cyan); background: rgba(0, 229, 255, 0.06); }
.option-letter { font-family: 'Bungee', cursive; font-size: 1.3rem; color: var(--cyan); background: rgba(0, 229, 255, 0.12); width: 44px; height: 44px; display: flex; align-items: center; justify-content: center; border-radius: 10px; flex-shrink: 0; border: 2px solid var(--cyan); }
.option-text { flex: 1; }
.option-text .eq { font-family: 'JetBrains Mono', monospace; }
.option-text.math { font-family: 'STIX Two Text', 'Cambria Math', 'Times New Roman', serif; font-size: 1.24em; font-weight: 500; line-height: 1.42; letter-spacing: 0.012em; font-variant-numeric: lining-nums; }
.option-text:not(.math) i.mv { font-size: 1.14em; line-height: 1; }
.option.correct { border-color: var(--green); background: rgba(57, 255, 20, 0.12); box-shadow: 0 0 26px rgba(57, 255, 20, 0.3); }
.option.correct .option-letter { background: var(--green); color: #000; border-color: var(--green); }
.option.incorrect { border-color: var(--red); background: rgba(255, 59, 59, 0.10); }
.option.incorrect .option-letter { background: var(--red); color: #fff; border-color: var(--red); }
.option.disabled { cursor: not-allowed; }
.option.faded { opacity: 0.35; }
@media (max-width: 700px) {
  .options { grid-template-columns: 1fr; }
  .question-card { padding: 24px 22px; }
}

/* Carried over from drill.html: without this the empty graph slot still
   claims a grid row and opens a dead 24px gap under the question. */
.question-card:not(.has-visual) .question-graph:empty { display: none; }