/* =============================================
   Bulgarian Study Tool — Shared Styles
   ============================================= */

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

/* --- Variables -------------------------------- */
:root {
  --bg:            #f9f9f7;
  --surface:       #ffffff;
  --border:        #e4e4e0;
  --text:          #1a1a1e;
  --text-2:        #5a5a6a;
  --text-3:        #9a9aaa;
  --green:         #2e7d32;
  --green-light:   #e8f5e9;
  --green-hover:   #1b5e20;
  --red:           #c62828;
  --red-light:     #ffebee;
  --amber:         #b45309;
  --amber-light:   #fef3c7;
  --shadow-s:      0 1px 3px rgba(0,0,0,.07);
  --shadow-m:      0 4px 12px rgba(0,0,0,.08);
  --radius:        12px;
  --radius-s:      8px;
  --nav-h:         60px;
}

/* --- Reset ------------------------------------ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 15px;
  min-height: 100vh;
}
a { color: inherit; text-decoration: none; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
ul { list-style: none; }
img { display: block; max-width: 100%; }

/* --- Navigation ------------------------------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 24px;
  gap: 8px;
}
.nav-brand {
  font-weight: 700;
  font-size: 16px;
  letter-spacing: -.3px;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}
.nav-brand .flag { font-size: 20px; line-height: 1; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 2px;
  margin-left: auto;
  flex-wrap: wrap;
}
.nav-link {
  padding: 6px 12px;
  border-radius: var(--radius-s);
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-2);
  transition: background .15s, color .15s;
}
.nav-link:hover { background: var(--bg); color: var(--text); }
.nav-link.active { background: var(--green-light); color: var(--green); }

/* --- Page header ------------------------------ */
.page-header {
  padding: 48px 24px 32px;
  max-width: 880px;
  margin: 0 auto;
}
.page-header h1 {
  font-size: clamp(26px, 4vw, 36px);
  font-weight: 700;
  letter-spacing: -.5px;
  line-height: 1.2;
  margin-bottom: 10px;
}
.page-header p {
  font-size: 16px;
  color: var(--text-2);
  max-width: 520px;
}

/* --- Container -------------------------------- */
.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

/* --- Badge / Tag ------------------------------ */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .3px;
  text-transform: uppercase;
}
.badge-green { background: var(--green-light); color: var(--green); }
.badge-red   { background: var(--red-light);   color: var(--red);   }
.badge-amber { background: var(--amber-light);  color: var(--amber); }

/* --- Buttons ---------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: var(--radius-s);
  font-size: 14px;
  font-weight: 600;
  transition: background .15s, transform .1s, box-shadow .15s;
}
.btn:active { transform: scale(.98); }
.btn-primary {
  background: var(--green);
  color: #fff;
  box-shadow: 0 2px 6px rgba(46,125,50,.25);
}
.btn-primary:hover { background: var(--green-hover); }
.btn-ghost {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-ghost:hover { background: var(--bg); }
.btn-sm { padding: 7px 14px; font-size: 13px; }
.btn-lg { padding: 13px 28px; font-size: 15px; }
.btn-icon {
  width: 40px; height: 40px;
  padding: 0;
  border-radius: var(--radius-s);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
}

/* --- Card ------------------------------------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-s);
}

/* --- Divider ---------------------------------- */
.divider { height: 1px; background: var(--border); margin: 24px 0; }

/* --- Section title ---------------------------- */
.section-title {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-3);
  margin-bottom: 16px;
}

/* --- Tabs ------------------------------------- */
.tabs {
  display: flex;
  gap: 4px;
  background: var(--bg);
  border: 1px solid var(--border);
  padding: 4px;
  border-radius: var(--radius-s);
  width: fit-content;
  margin-bottom: 28px;
}
.tab-btn {
  padding: 8px 18px;
  border-radius: 6px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-2);
  transition: background .15s, color .15s;
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active {
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow-s);
}

/* --- Progress bar ----------------------------- */
.progress-track {
  height: 6px;
  background: var(--border);
  border-radius: 99px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: var(--green);
  border-radius: 99px;
  transition: width .4s ease;
}

/* --- Footer ----------------------------------- */
.footer {
  border-top: 1px solid var(--border);
  padding: 20px 24px;
  text-align: center;
  font-size: 13px;
  color: var(--text-3);
}

/* ============================================= */
/*  Study Plan (index.html)                       */
/* ============================================= */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 12px;
  margin-bottom: 40px;
}
.stat-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  box-shadow: var(--shadow-s);
}
.stat-card .stat-num {
  font-size: 28px;
  font-weight: 700;
  color: var(--green);
  letter-spacing: -1px;
  line-height: 1;
  margin-bottom: 4px;
}
.stat-card .stat-label {
  font-size: 13px;
  color: var(--text-2);
  font-weight: 500;
}

.weeks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 16px;
}
.week-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-s);
  overflow: hidden;
}
.week-card summary {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 20px;
  cursor: pointer;
  list-style: none;
  user-select: none;
  transition: background .15s;
}
.week-card summary::-webkit-details-marker { display: none; }
.week-card summary:hover { background: var(--bg); }
.week-num {
  min-width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--green-light);
  color: var(--green);
  font-weight: 700;
  font-size: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.week-meta { flex: 1; }
.week-title { font-weight: 600; font-size: 14.5px; line-height: 1.3; }
.week-sub   { font-size: 12.5px; color: var(--text-2); margin-top: 2px; }
.week-chevron {
  font-size: 12px;
  color: var(--text-3);
  transition: transform .2s;
}
details[open] .week-chevron { transform: rotate(90deg); }
.week-body {
  padding: 0 20px 18px;
  border-top: 1px solid var(--border);
}
.week-body ul { display: flex; flex-direction: column; gap: 6px; padding-top: 14px; }
.week-body li {
  display: flex;
  gap: 8px;
  font-size: 13.5px;
  color: var(--text-2);
}
.week-body li::before {
  content: '•';
  color: var(--green);
  flex-shrink: 0;
  margin-top: 1px;
}
.week-time {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 12px;
  color: var(--text-3);
  margin-top: 12px;
  padding: 4px 10px;
  background: var(--bg);
  border-radius: 20px;
}

/* ============================================= */
/*  Alphabet Trainer (alphabet.html)              */
/* ============================================= */
.alpha-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  gap: 10px;
}
.alpha-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 12px 12px;
  text-align: center;
  cursor: pointer;
  transition: border-color .15s, box-shadow .15s, transform .1s;
}
.alpha-card:hover {
  border-color: var(--green);
  box-shadow: 0 0 0 3px var(--green-light);
  transform: translateY(-2px);
}
.alpha-card.selected {
  border-color: var(--green);
  background: var(--green-light);
}
.alpha-letter {
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
  margin-bottom: 4px;
}
.alpha-lower {
  font-size: 18px;
  color: var(--text-2);
  margin-bottom: 6px;
}
.alpha-sound {
  font-size: 11px;
  color: var(--text-3);
  font-family: monospace;
}

.letter-detail {
  background: var(--surface);
  border: 2px solid var(--green);
  border-radius: var(--radius);
  padding: 24px 28px;
  margin-bottom: 24px;
  display: none;
  animation: fade-in .2s ease;
}
.letter-detail.visible { display: block; }
.letter-detail-inner {
  display: flex;
  gap: 28px;
  align-items: flex-start;
  flex-wrap: wrap;
}
.detail-big {
  font-size: 80px;
  font-weight: 700;
  line-height: 1;
  color: var(--green);
}
.detail-info h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.detail-info p  { font-size: 14px; color: var(--text-2); margin-bottom: 6px; }

/* Quiz mode */
.quiz-wrap {
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
}
.quiz-letter {
  font-size: 96px;
  font-weight: 700;
  line-height: 1;
  color: var(--text);
  margin: 32px 0;
  animation: fade-in .25s ease;
}
.quiz-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 24px;
}
.quiz-option {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 12px;
  font-size: 15px;
  font-weight: 500;
  transition: border-color .15s, background .15s, transform .1s;
}
.quiz-option:hover:not(:disabled) {
  border-color: var(--text-2);
  transform: translateY(-1px);
}
.quiz-option.correct {
  border-color: var(--green) !important;
  background: var(--green-light) !important;
  color: var(--green);
}
.quiz-option.wrong {
  border-color: var(--red) !important;
  background: var(--red-light) !important;
  color: var(--red);
}
.quiz-option:disabled { opacity: .7; pointer-events: none; }
.quiz-score {
  display: flex;
  justify-content: center;
  gap: 24px;
  font-size: 14px;
  font-weight: 600;
  padding: 14px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 28px;
}
.quiz-score .s-correct { color: var(--green); }
.quiz-score .s-wrong   { color: var(--red); }
.quiz-score .s-total   { color: var(--text-2); }
.quiz-feedback {
  min-height: 28px;
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
  animation: fade-in .2s ease;
}
.quiz-feedback.ok  { color: var(--green); }
.quiz-feedback.bad { color: var(--red); }

/* ============================================= */
/*  Flashcards (flashcards.html)                  */
/* ============================================= */
.category-chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 28px;
}
.chip {
  padding: 7px 16px;
  border-radius: 99px;
  border: 1.5px solid var(--border);
  font-size: 13px;
  font-weight: 500;
  background: var(--surface);
  color: var(--text-2);
  cursor: pointer;
  transition: border-color .15s, background .15s, color .15s;
}
.chip:hover  { border-color: var(--text-2); color: var(--text); }
.chip.active { border-color: var(--green); background: var(--green-light); color: var(--green); }

.flashcard-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}
.flashcard-counter {
  font-size: 13px;
  color: var(--text-3);
  font-weight: 500;
}
.flashcard-scene {
  width: 100%;
  max-width: 460px;
  height: 260px;
  perspective: 900px;
  cursor: pointer;
}
.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform .5s cubic-bezier(.4,0,.2,1);
}
.flashcard-scene.flipped .flashcard-inner { transform: rotateY(180deg); }
.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-m);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 28px;
  text-align: center;
  gap: 10px;
}
.flashcard-front { background: var(--surface); }
.flashcard-back  { background: var(--green-light); transform: rotateY(180deg); }
.card-tap-hint { font-size: 12px; color: var(--text-3); position: absolute; bottom: 14px; }
.card-bg-word {
  font-size: 40px;
  font-weight: 700;
  letter-spacing: -1px;
  color: var(--text);
  line-height: 1.1;
}
.card-bg-category { font-size: 12px; color: var(--text-3); text-transform: uppercase; letter-spacing: .5px; }
.card-en-word {
  font-size: 30px;
  font-weight: 700;
  color: var(--green);
  line-height: 1.1;
}
.card-en-roman {
  font-size: 15px;
  color: var(--text-2);
  font-style: italic;
}
.card-en-example {
  font-size: 13px;
  color: var(--text-2);
  font-style: italic;
}

.flashcard-controls {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}
.know-btn {
  background: var(--green-light);
  color: var(--green);
  border: 1.5px solid var(--green);
  padding: 10px 22px;
  border-radius: var(--radius-s);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.know-btn:hover { background: var(--green); color: #fff; }
.skip-btn {
  background: var(--red-light);
  color: var(--red);
  border: 1.5px solid var(--red);
  padding: 10px 22px;
  border-radius: var(--radius-s);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.skip-btn:hover { background: var(--red); color: #fff; }

.flashcard-progress {
  width: 100%;
  max-width: 460px;
}
.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-3);
  margin-bottom: 6px;
}

.deck-complete {
  text-align: center;
  padding: 48px 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  max-width: 460px;
  width: 100%;
  display: none;
}
.deck-complete.visible { display: block; }
.deck-complete .big-emoji { font-size: 52px; margin-bottom: 12px; }
.deck-complete h3 { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.deck-complete p  { font-size: 14px; color: var(--text-2); margin-bottom: 20px; }
.deck-stats { display: flex; justify-content: center; gap: 28px; margin-bottom: 24px; }
.deck-stat { text-align: center; }
.deck-stat-val { font-size: 24px; font-weight: 700; }
.deck-stat-lbl { font-size: 12px; color: var(--text-2); }

/* ============================================= */
/*  Phrases (phrases.html)                        */
/* ============================================= */
.search-bar {
  display: flex;
  margin-bottom: 28px;
  max-width: 360px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-s);
  overflow: hidden;
  background: var(--surface);
  transition: border-color .15s;
}
.search-bar:focus-within { border-color: var(--green); }
.search-input {
  flex: 1;
  padding: 10px 14px;
  border: none;
  font-family: inherit;
  font-size: 14px;
  outline: none;
  background: transparent;
  color: var(--text);
}
.search-input::placeholder { color: var(--text-3); }
.search-clear {
  padding: 10px 14px;
  background: transparent;
  color: var(--text-3);
  font-size: 16px;
  cursor: pointer;
  transition: color .15s;
}
.search-clear:hover { color: var(--text); }

.phrase-category { margin-bottom: 36px; }
.phrase-category-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.phrase-category-title .cat-icon { font-size: 18px; }
.phrase-list { display: flex; flex-direction: column; gap: 6px; }
.phrase-row {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-s);
  padding: 13px 16px;
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 6px 16px;
  align-items: center;
  cursor: pointer;
  transition: border-color .15s, box-shadow .15s;
}
.phrase-row:hover {
  border-color: var(--green);
  box-shadow: 0 0 0 2px var(--green-light);
}
.phrase-row.hidden { display: none; }
.p-bg {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
}
.p-roman {
  font-size: 13px;
  color: var(--text-2);
  font-style: italic;
}
.p-en {
  font-size: 13px;
  color: var(--text-3);
}
.phrase-header-row {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 6px 16px;
  padding: 6px 16px;
  margin-bottom: 2px;
}
.phrase-header-row span {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  color: var(--text-3);
}

.phrase-copied-toast {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--text);
  color: #fff;
  padding: 10px 20px;
  border-radius: 99px;
  font-size: 13px;
  font-weight: 500;
  opacity: 0;
  transition: opacity .25s, transform .25s;
  pointer-events: none;
  z-index: 999;
}
.phrase-copied-toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Mobile responsive */
@media (max-width: 480px) {
  .phrase-row { grid-template-columns: 1fr 1fr; }
  .p-en { display: none; }
  .phrase-header-row { grid-template-columns: 1fr 1fr; }
  .phrase-header-row span:last-child { display: none; }
  .weeks-grid { grid-template-columns: 1fr; }
  .alpha-grid { grid-template-columns: repeat(5, 1fr); }
  .quiz-options { grid-template-columns: 1fr; }
  .nav { padding: 0 14px; }
  .page-header { padding: 28px 16px 20px; }
  .container { padding: 0 16px 60px; }
}

/* Animations */
@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}