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

:root {
  --bg:        #0a0a0f;
  --surface:   #12121a;
  --border:    #2a2a3a;
  --html:      #ff6b35;
  --css:       #00d4ff;
  --js:        #f7c948;
  --easy:      #4ade80;
  --medium:    #fb923c;
  --hard:      #f43f5e;
  --text:      #e8e8f0;
  --muted:     #6b6b80;
  --correct:   #4ade80;
  --wrong:     #f43f5e;
  --font-head: 'Orbitron', monospace;
  --font-body: 'Share Tech Mono', monospace;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  overflow: hidden;
}

/* ============ GRID BACKGROUND ============ */
.bg-grid {
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.02) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}

/* ============ SCREENS ============ */
.screen {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 2rem;
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: opacity .35s ease, transform .35s ease;
  z-index: 1;
}

.screen.active {
  opacity: 1;
  pointer-events: all;
  transform: translateY(0);
}

/* ============ LIGHTNING ============ */
.lightning-bolt {
  font-size: 4rem;
  animation: pulse 2s ease-in-out infinite;
  line-height: 1;
}

@keyframes pulse {
  0%, 100% { transform: scale(1);   filter: drop-shadow(0 0 8px #f7c948); }
  50%       { transform: scale(1.1); filter: drop-shadow(0 0 20px #f7c948); }
}

/* ============ TITLES ============ */
.main-title {
  font-family: var(--font-head);
  font-size: clamp(2.5rem, 8vw, 5rem);
  font-weight: 900;
  letter-spacing: .15em;
  color: var(--text);
  text-shadow: 0 0 30px rgba(247,201,72,.3);
}

.subtitle {
  font-size: 1rem;
  color: var(--muted);
  letter-spacing: .2em;
  text-transform: uppercase;
}

/* ============ BUTTON GROUP ============ */
.btn-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: .5rem;
}

/* ============ BUTTONS ============ */
.btn {
  font-family: var(--font-head);
  font-size: .85rem;
  font-weight: 700;
  letter-spacing: .1em;
  padding: .9rem 2rem;
  border: 2px solid;
  border-radius: 4px;
  background: transparent;
  cursor: pointer;
  transition: all .2s ease;
  position: relative;
  overflow: hidden;
  text-transform: uppercase;
}

.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity .2s ease;
}

.btn:hover::before { opacity: .12; }

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,.4);
}

.btn:active { transform: translateY(0); }

/* Color variants */
.btn-html  { color: var(--html); border-color: var(--html); }
.btn-html::before  { background: var(--html); }
.btn-html:hover    { box-shadow: 0 8px 20px rgba(255,107,53,.3); }

.btn-css   { color: var(--css);  border-color: var(--css); }
.btn-css::before   { background: var(--css); }
.btn-css:hover     { box-shadow: 0 8px 20px rgba(0,212,255,.3); }

.btn-js    { color: var(--js);   border-color: var(--js); }
.btn-js::before    { background: var(--js); }
.btn-js:hover      { box-shadow: 0 8px 20px rgba(247,201,72,.3); }

.btn-l1    { color: var(--easy);   border-color: var(--easy); }
.btn-l1::before    { background: var(--easy); }
.btn-l1:hover      { box-shadow: 0 8px 20px rgba(74,222,128,.3); }

.btn-l2    { color: var(--medium); border-color: var(--medium); }
.btn-l2::before    { background: var(--medium); }
.btn-l2:hover      { box-shadow: 0 8px 20px rgba(251,146,60,.3); }

.btn-l3    { color: var(--hard);   border-color: var(--hard); }
.btn-l3::before    { background: var(--hard); }
.btn-l3:hover      { box-shadow: 0 8px 20px rgba(244,63,94,.3); }

.btn-next  { color: var(--text); border-color: var(--border); margin-top: .5rem; }
.btn-next:hover { border-color: var(--text); box-shadow: 0 8px 20px rgba(0,0,0,.3); }

/* Tags on level buttons */
.tag {
  font-family: var(--font-body);
  font-size: .65rem;
  letter-spacing: .05em;
  opacity: .7;
  margin-left: .5rem;
}

/* ============ BACK BUTTON ============ */
.back-btn {
  position: absolute;
  top: 1.5rem;
  left: 1.5rem;
  font-family: var(--font-body);
  font-size: .85rem;
  color: var(--muted);
  background: none;
  border: none;
  cursor: pointer;
  transition: color .2s;
  z-index: 10;
}

.back-btn:hover { color: var(--text); }

/* ============ QUIZ HEADER ============ */
.quiz-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  width: 100%;
  max-width: 600px;
}

.quiz-label {
  font-family: var(--font-head);
  font-size: .75rem;
  letter-spacing: .15em;
  padding: .3rem .8rem;
  border-radius: 3px;
  text-transform: uppercase;
}

.quiz-label.lang-html { color: var(--html); border: 1px solid var(--html); }
.quiz-label.lang-css  { color: var(--css);  border: 1px solid var(--css);  }
.quiz-label.lang-js   { color: var(--js);   border: 1px solid var(--js);   }

.quiz-progress {
  margin-left: auto;
  font-size: .85rem;
  color: var(--muted);
}

/* ============ QUESTION CARD ============ */
.question-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 2rem;
  width: 100%;
  max-width: 600px;
}

.question-text {
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
  color: var(--text);
}

/* ============ OPTIONS ============ */
.options-container {
  display: flex;
  flex-direction: column;
  gap: .75rem;
}

.option-btn {
  font-family: var(--font-body);
  font-size: .9rem;
  text-align: left;
  padding: .85rem 1.2rem;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  cursor: pointer;
  transition: all .15s ease;
}

.option-btn:hover:not(:disabled) {
  border-color: var(--muted);
  background: rgba(255,255,255,.03);
}

.option-btn.correct {
  border-color: var(--correct);
  color: var(--correct);
  background: rgba(74,222,128,.07);
}

.option-btn.wrong {
  border-color: var(--wrong);
  color: var(--wrong);
  background: rgba(244,63,94,.07);
}

.option-btn:disabled { cursor: default; }

/* ============ FEEDBACK ============ */
.feedback {
  font-size: .9rem;
  padding: .6rem 1.2rem;
  border-radius: 4px;
  width: 100%;
  max-width: 600px;
  text-align: center;
}

.feedback.correct-fb { color: var(--correct); background: rgba(74,222,128,.08); border: 1px solid rgba(74,222,128,.2); }
.feedback.wrong-fb   { color: var(--wrong);   background: rgba(244,63,94,.08);  border: 1px solid rgba(244,63,94,.2); }
.feedback.hidden     { display: none; }

/* ============ RESULT ============ */
.result-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 3rem 2.5rem;
  text-align: center;
  max-width: 420px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.2rem;
}

.result-emoji { font-size: 3.5rem; }

.result-title {
  font-family: var(--font-head);
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: .1em;
}

.result-score {
  font-size: 1rem;
  color: var(--muted);
}

.result-btns {
  display: flex;
  gap: 1rem;
  margin-top: .5rem;
  flex-wrap: wrap;
  justify-content: center;
}

/* ============ RESPONSIVE ============ */
@media (max-width: 480px) {
  .btn-group { flex-direction: column; align-items: center; }
  .btn       { width: 220px; text-align: center; }
  .question-card { padding: 1.5rem; }
}