/* ============================================================
   StudyLens — design tokens
   Palette: graph-paper notebook + camera viewfinder
   ============================================================ */
:root {
  --paper: #fbfaf5;          /* warm paper white */
  --grid: #e8e6da;           /* graph-paper line */
  --ink: #21303f;            /* deep ink */
  --ink-soft: #5c6b7a;       /* muted ink */
  --blue: #2b59c3;           /* ballpoint blue */
  --highlight: #ffe14d;      /* highlighter yellow */
  --red-pen: #e4572e;        /* teacher's red pen */
  --card: #ffffff;
  --radius: 14px;
  --font-display: "Space Grotesk", sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font-body);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 28px 28px;
  min-height: 100vh;
}

main { max-width: 880px; margin: 0 auto; padding: 0 20px 60px; }

.hidden { display: none !important; }
.muted { color: var(--ink-soft); font-size: 0.9rem; }

/* ============ Topbar ============ */
.topbar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 16px 24px; position: sticky; top: 0; z-index: 20;
  background: rgba(251, 250, 245, 0.9); backdrop-filter: blur(6px);
  border-bottom: 1.5px solid var(--ink);
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-lens {
  width: 22px; height: 22px; border-radius: 50%;
  border: 3px solid var(--ink); position: relative; display: inline-block;
}
.brand-lens::after {
  content: ""; position: absolute; inset: 4px;
  border-radius: 50%; background: var(--blue);
}
.brand-name { font-family: var(--font-display); font-weight: 700; font-size: 1.35rem; letter-spacing: -0.02em; }
.brand-name em { font-style: normal; color: var(--blue); }
.topbar-right { display: flex; align-items: center; gap: 10px; }
.model-badge {
  font-family: var(--font-mono); font-size: 0.72rem;
  background: var(--ink); color: var(--paper);
  padding: 4px 10px; border-radius: 999px;
}

/* ============ Buttons ============ */
.primary-btn, .secondary-btn, .ghost-btn {
  font-family: var(--font-display); font-weight: 500; font-size: 0.95rem;
  border-radius: 10px; padding: 10px 18px; cursor: pointer;
  transition: transform 0.08s ease, box-shadow 0.08s ease;
  text-decoration: none; display: inline-flex; align-items: center; gap: 6px;
}
.primary-btn {
  background: var(--blue); color: #fff; border: 2px solid var(--ink);
  box-shadow: 3px 3px 0 var(--ink);
}
.primary-btn:hover { transform: translate(-1px, -1px); box-shadow: 4px 4px 0 var(--ink); }
.primary-btn:active { transform: translate(2px, 2px); box-shadow: 1px 1px 0 var(--ink); }
.primary-btn:disabled { opacity: 0.5; cursor: wait; }
.secondary-btn {
  background: var(--highlight); color: var(--ink); border: 2px solid var(--ink);
  box-shadow: 3px 3px 0 var(--ink);
}
.secondary-btn:hover { transform: translate(-1px, -1px); box-shadow: 4px 4px 0 var(--ink); }
.secondary-btn:disabled { opacity: 0.45; cursor: not-allowed; box-shadow: none; transform: none; }
.ghost-btn {
  background: transparent; border: 1.5px solid var(--ink-soft); color: var(--ink);
}
.ghost-btn:hover { border-color: var(--ink); background: #fff; }

/* ============ Settings ============ */
.settings-panel {
  max-width: 560px; margin: 24px auto; padding: 24px;
  background: var(--card); border: 2px solid var(--ink);
  border-radius: var(--radius); box-shadow: 5px 5px 0 var(--ink);
}
.settings-panel h2 { font-family: var(--font-display); margin-bottom: 6px; }
.field { display: block; margin: 16px 0; }
.field span { display: block; font-weight: 600; font-size: 0.85rem; margin-bottom: 6px; }
.field input, .field select {
  width: 100%; padding: 10px 12px; font-family: var(--font-mono); font-size: 0.9rem;
  border: 1.5px solid var(--ink-soft); border-radius: 8px; background: var(--paper);
}
.field input:focus, .field select:focus { outline: 2px solid var(--blue); border-color: var(--blue); }
.row-gap { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }

/* ============ Hero ============ */
.hero { text-align: center; padding: 48px 0 28px; }
.hero h1 {
  font-family: var(--font-display); font-weight: 700;
  font-size: clamp(1.8rem, 5vw, 3rem); line-height: 1.15; letter-spacing: -0.03em;
}
.hl {
  background: linear-gradient(transparent 55%, var(--highlight) 55%, var(--highlight) 92%, transparent 92%);
  padding: 0 4px;
}
.hero-sub { margin-top: 14px; color: var(--ink-soft); font-size: 1.05rem; max-width: 560px; margin-inline: auto; }

/* ============ Capture zone / viewfinder ============ */
.capture-zone { margin-top: 8px; }
.viewfinder {
  position: relative; background: var(--card);
  border: 2px dashed var(--ink-soft); border-radius: var(--radius);
  padding: 36px 24px; min-height: 200px;
  display: flex; align-items: center; justify-content: center;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.viewfinder.dragover { border-color: var(--blue); background: #eef3ff; }
.vf-corner {
  position: absolute; width: 26px; height: 26px; border: 3.5px solid var(--red-pen);
}
.vf-corner.tl { top: -3px; left: -3px; border-right: none; border-bottom: none; border-radius: 10px 0 0 0; }
.vf-corner.tr { top: -3px; right: -3px; border-left: none; border-bottom: none; border-radius: 0 10px 0 0; }
.vf-corner.bl { bottom: -3px; left: -3px; border-right: none; border-top: none; border-radius: 0 0 0 10px; }
.vf-corner.br { bottom: -3px; right: -3px; border-left: none; border-top: none; border-radius: 0 0 10px 0; }

.capture-idle { text-align: center; }
.capture-hint { color: var(--ink-soft); margin-bottom: 14px; }
.capture-hint.small { font-size: 0.82rem; margin-top: 14px; margin-bottom: 0; }
.capture-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.camera-live { width: 100%; text-align: center; }
.camera-live video { width: 100%; max-height: 420px; border-radius: 10px; border: 2px solid var(--ink); background: #000; }
.camera-controls { margin-top: 12px; display: flex; gap: 12px; justify-content: center; }

.preview-wrap { text-align: center; width: 100%; }
.preview-wrap img { max-width: 100%; max-height: 380px; border-radius: 10px; border: 2px solid var(--ink); }
.clear-img { margin-top: 10px; }

/* ============ Modes ============ */
.modes { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin: 22px 0 14px; }
.mode-chip {
  font-family: var(--font-display); font-size: 0.92rem; cursor: pointer;
  padding: 8px 16px; border-radius: 999px;
  background: var(--card); border: 2px solid var(--ink-soft); color: var(--ink-soft);
}
.mode-chip.active {
  background: var(--ink); color: var(--paper); border-color: var(--ink);
  box-shadow: 2px 2px 0 var(--red-pen);
}

/* ============ Ask bar ============ */
.ask-bar {
  display: flex; gap: 10px; align-items: flex-end;
  background: var(--card); border: 2px solid var(--ink);
  border-radius: var(--radius); padding: 10px; box-shadow: 4px 4px 0 var(--ink);
}
.ask-bar textarea {
  flex: 1; border: none; resize: none; font-family: var(--font-body);
  font-size: 0.97rem; padding: 8px; background: transparent; max-height: 140px;
}
.ask-bar textarea:focus { outline: none; }
#micBtn.recording { border-color: var(--red-pen); color: var(--red-pen); animation: pulse 1s infinite; }
@keyframes pulse { 50% { box-shadow: 0 0 0 5px rgba(228, 87, 46, 0.25); } }

/* ============ Chat ============ */
.chat { margin-top: 26px; display: flex; flex-direction: column; gap: 16px; }
.msg { max-width: 92%; padding: 14px 18px; border-radius: var(--radius); line-height: 1.55; font-size: 0.96rem; }
.msg.user {
  align-self: flex-end; background: var(--blue); color: #fff;
  border: 2px solid var(--ink); border-bottom-right-radius: 4px;
}
.msg.user img { max-width: 180px; border-radius: 8px; display: block; margin-top: 8px; }
.msg.ai {
  align-self: flex-start; background: var(--card); border: 2px solid var(--ink);
  border-bottom-left-radius: 4px; box-shadow: 3px 3px 0 rgba(33, 48, 63, 0.15);
}
.msg.ai .who {
  font-family: var(--font-display); font-size: 0.75rem; font-weight: 700;
  color: var(--red-pen); text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 6px;
}
.msg.ai.thinking { color: var(--ink-soft); font-style: italic; }
.msg.ai h1, .msg.ai h2, .msg.ai h3 { font-family: var(--font-display); margin: 10px 0 6px; font-size: 1.02rem; }
.msg.ai p { margin: 6px 0; }
.msg.ai ul, .msg.ai ol { margin: 6px 0 6px 20px; }
.msg.ai code {
  font-family: var(--font-mono); font-size: 0.85em;
  background: var(--paper); border: 1px solid var(--grid); padding: 1px 5px; border-radius: 5px;
}
.msg.ai pre { background: var(--ink); color: var(--paper); padding: 12px; border-radius: 8px; overflow-x: auto; margin: 8px 0; }
.msg.ai pre code { background: none; border: none; color: inherit; }
.msg.ai strong { background: linear-gradient(transparent 60%, var(--highlight) 60%); }
.msg.ai blockquote {
  border-left: 3px solid var(--red-pen); background: var(--paper);
  padding: 8px 12px; margin: 8px 0; border-radius: 0 8px 8px 0; color: var(--ink-soft);
}

/* Quiz cards */
.quiz-q { border-top: 1.5px dashed var(--grid); padding-top: 10px; margin-top: 10px; }
.quiz-q:first-child { border-top: none; margin-top: 0; padding-top: 0; }
.quiz-topic { font-family: var(--font-mono); font-size: 0.7rem; color: var(--ink-soft); text-transform: uppercase; letter-spacing: 0.06em; }
.quiz-options { display: flex; flex-direction: column; gap: 8px; margin-top: 8px; }
.quiz-opt {
  text-align: left; padding: 9px 14px; border-radius: 9px; cursor: pointer;
  background: var(--paper); border: 1.5px solid var(--ink-soft); font-size: 0.92rem; font-family: var(--font-body);
}
.quiz-opt:hover:not(:disabled) { border-color: var(--blue); background: #eef3ff; }
.quiz-opt.correct { background: #e5f7e9; border-color: #2e8b57; font-weight: 600; }
.quiz-opt.wrong { background: #fdeae4; border-color: var(--red-pen); }
.quiz-opt:disabled { cursor: default; }
.quiz-expl { margin-top: 8px; font-size: 0.88rem; color: var(--ink-soft); border-left: 3px solid var(--highlight); padding-left: 10px; }

/* Flashcards */
.cards-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; margin-top: 8px; }
.flashcard { perspective: 900px; height: 150px; cursor: pointer; }
.flashcard-inner {
  position: relative; width: 100%; height: 100%;
  transition: transform 0.45s; transform-style: preserve-3d;
}
.flashcard.flipped .flashcard-inner { transform: rotateY(180deg); }
.fc-face {
  position: absolute; inset: 0; backface-visibility: hidden;
  display: flex; align-items: center; justify-content: center; text-align: center;
  padding: 14px; border-radius: 10px; border: 2px solid var(--ink); font-size: 0.9rem;
}
.fc-front { background: var(--highlight); font-family: var(--font-display); font-weight: 500; }
.fc-back { background: var(--card); transform: rotateY(180deg); }

/* ============ Weak spots ============ */
.weakspots {
  margin-top: 34px; background: var(--card); border: 2px solid var(--ink);
  border-radius: var(--radius); padding: 18px 20px; box-shadow: 4px 4px 0 var(--ink);
}
.ws-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; }
.ws-head h3 { font-family: var(--font-display); }
.ws-list { margin-top: 12px; display: flex; gap: 8px; flex-wrap: wrap; }
.ws-tag {
  font-family: var(--font-mono); font-size: 0.78rem;
  background: #fdeae4; color: var(--red-pen); border: 1.5px solid var(--red-pen);
  border-radius: 999px; padding: 4px 12px; display: inline-flex; align-items: center; gap: 6px;
}
.ws-tag button { border: none; background: none; cursor: pointer; color: var(--red-pen); font-weight: 700; }

/* ============ Footer ============ */
.footer { text-align: center; padding: 26px 16px 40px; color: var(--ink-soft); font-size: 0.85rem; border-top: 1.5px solid var(--grid); margin-top: 40px; }
.footer a { color: var(--blue); }

/* ============ Responsive & a11y ============ */
@media (max-width: 560px) {
  .ask-bar { flex-wrap: wrap; }
  .ask-bar textarea { min-width: 100%; }
  .msg { max-width: 100%; }
}
:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}