/* ===== GLOBAL THEME (Dark Theme) ===== */
:root {
  --saffron: #FF9933;
  --green: #138808;
  --bg-dark: #0a0e27;
  --card-bg: #1a1f4e;
  --text-light: #ffffff;
  --text-muted: #b8c1ec;
}

body {
  background: radial-gradient(circle at 50% 50%, #1a1f4e 0%, #0a0e27 100%);
  font-family: 'Poppins', sans-serif;
  color: var(--text-light);
  margin: 0;
  overflow-x: hidden;
}

.reveal { font-family: 'Poppins', sans-serif; color: var(--text-light); }
.reveal h1, .reveal h2, .reveal h3 { font-family: 'Poppins', sans-serif; text-transform: none; font-weight: 800; letter-spacing: -1px; color: #ffffff; }
.hindi { font-family: 'Tiro Devanagari Hindi', serif; }

/* ===== SLIDE OVERFLOW FIX (Auto-fit) ===== */
.reveal .slides section {
  text-align: center; padding: 15px; overflow-y: auto !important; 
  height: 100%; box-sizing: border-box; display: flex; flex-direction: column; justify-content: center;
}
.reveal .slides section::-webkit-scrollbar { display: none; }
.reveal .slides section { -ms-overflow-style: none; scrollbar-width: none; }

/* ===== TITLE SLIDE ===== */
.title-slide h1 { font-size: 4em; color: #ffffff; margin-bottom: 0.1em; }
.title-slide .hindi-title {
  font-family: 'Tiro Devanagari Hindi', serif; font-size: 6em; color: var(--saffron);
  margin: 0.1em 0; text-shadow: 0 0 30px rgba(255, 153, 51, 0.4);
}
.title-slide p { font-size: 1.3em; color: var(--text-muted); font-weight: 400; }
.flag-strip {
  display: inline-block; width: 250px; height: 8px;
  background: linear-gradient(90deg, var(--saffron) 33%, #ffffff 33% 66%, var(--green) 66%);
  border-radius: 4px; margin: 25px auto; box-shadow: 0 0 20px rgba(255,255,255,0.2);
}

/* ===== CARDS & GRIDS ===== */
.letter-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; margin-top: 25px; max-width: 1100px; margin-left: auto; margin-right: auto; }
.letter-grid.cols-3 { grid-template-columns: repeat(3, 1fr); max-width: 900px; }
.letter-grid.cols-5 { grid-template-columns: repeat(5, 1fr); max-width: 1150px; }

.letter-card {
  background: var(--card-bg); border: 2px solid rgba(255, 153, 51, 0.3);
  border-radius: 16px; padding: 20px 10px; transition: all 0.3s ease;
  cursor: pointer; box-shadow: 0 4px 15px rgba(0,0,0,0.3); position: relative; backdrop-filter: blur(10px);
}
.letter-card:hover {
  transform: translateY(-8px) scale(1.05); border-color: var(--saffron);
  box-shadow: 0 15px 40px rgba(255, 153, 51, 0.4); background: rgba(255, 153, 51, 0.1);
}
.letter-card .dev { font-family: 'Tiro Devanagari Hindi', serif; font-size: 3.2em; color: var(--saffron); line-height: 1.1; margin-bottom: 8px; }
.letter-card .roman { font-size: 1.3em; font-weight: 600; color: #ffffff; margin-bottom: 4px; }
.letter-card .sound { font-size: 0.85em; color: var(--text-muted); font-weight: 400; }
.letter-card .audio-icon { position: absolute; top: 10px; right: 12px; font-size: 0.9em; color: rgba(255,255,255,0.3); transition: color 0.3s; }
.letter-card:hover .audio-icon { color: var(--green); }

/* ===== HEADERS & TEXT ===== */
.section-header { font-size: 3em; margin-bottom: 10px; color: #ffffff; }
.section-header .hindi { color: var(--saffron); display: block; font-size: 1.3em; margin-top: 10px; }
.subtitle { font-size: 1.1em; color: var(--text-muted); font-weight: 400; margin-bottom: 20px; }

/* ===== INFO BOXES ===== */
.info-box {
  background: rgba(255, 255, 255, 0.05); border-left: 6px solid var(--saffron);
  padding: 20px 30px; border-radius: 12px; text-align: left;
  max-width: 900px; margin: 15px auto; font-size: 1em; box-shadow: 0 4px 15px rgba(0,0,0,0.2); color: var(--text-light);
}
.info-box strong { color: var(--saffron); }

/* ===== EXAMPLES ===== */
.example-row { display: flex; justify-content: center; gap: 20px; margin-top: 20px; flex-wrap: wrap; }
.example-item {
  background: rgba(255, 255, 255, 0.05); border-radius: 14px; padding: 20px 25px; min-width: 150px;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2); border: 1px solid rgba(255,255,255,0.1); cursor: pointer; transition: all 0.3s;
}
.example-item:hover { border-color: var(--saffron); background: rgba(255, 153, 51, 0.1); }
.example-item .dev { font-family: 'Tiro Devanagari Hindi', serif; font-size: 2.2em; color: var(--saffron); }
.example-item .roman { font-size: 1em; color: #ffffff; font-weight: 600; margin-top: 5px; }
.example-item .meaning { font-size: 0.85em; color: var(--text-muted); margin-top: 3px; }

/* ===== EXERCISE CARDS ===== */
.exercise-card {
  background: rgba(255, 255, 255, 0.03); border: 2px solid rgba(19, 136, 8, 0.4);
  border-radius: 16px; padding: 20px 25px; margin: 15px auto; max-width: 850px; text-align: left;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}
.exercise-card p { font-size: 1.2em; margin-bottom: 10px; color: #ffffff; font-weight: 600; }
.exercise-card .options { font-family: 'Tiro Devanagari Hindi', serif; font-size: 1.4em; color: var(--saffron); margin: 15px 0; letter-spacing: 10px; }
.reveal-btn {
  background: var(--green); color: #fff; border: none; padding: 10px 25px; border-radius: 8px;
  cursor: pointer; font-weight: 600; font-size: 1em; transition: background 0.3s; font-family: 'Poppins', sans-serif;
}
.reveal-btn:hover { background: var(--saffron); }
.answer {
  display: none; margin-top: 15px; font-size: 1.5em; color: var(--saffron); font-weight: 700;
  font-family: 'Tiro Devanagari Hindi', serif; padding: 10px; background: rgba(255, 153, 51, 0.1);
  border-radius: 8px; border-left: 4px solid var(--saffron);
}

/* ===== PROGRESS BAR & CONTROLS ===== */
.reveal .progress { background: rgba(255,255,255,0.1); height: 6px; }
.reveal .progress span { background: linear-gradient(90deg, var(--saffron), var(--green)); }
.reveal .controls { color: var(--saffron); }

/* ===== AUTO-FIT FOR DENSE SLIDES ===== */
.dense-slide .section-header { font-size: 2.5em; }
.dense-slide .subtitle { font-size: 0.95em; margin-bottom: 10px; }
.dense-slide .info-box { padding: 15px 20px; font-size: 0.9em; margin: 10px auto; }
.dense-slide .letter-card { padding: 15px 5px; }
.dense-slide .letter-card .dev { font-size: 2.5em; }
.dense-slide .letter-card .roman { font-size: 1.1em; }
.dense-slide .letter-card .sound { font-size: 0.75em; }

/* ===== MOBILE RESPONSIVE ===== */
@media (max-width: 768px) {
  .reveal .slides section { padding: 10px !important; }
  .title-slide h1 { font-size: 2.5em; }
  .title-slide .hindi-title { font-size: 3.5em; }
  .section-header { font-size: 2em; }
  .section-header .hindi { font-size: 1em; }
  .letter-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .letter-grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
  .letter-grid.cols-5 { grid-template-columns: repeat(2, 1fr); }
  .letter-card .dev { font-size: 2.5em; }
  .letter-card .roman { font-size: 1.1em; }
  .letter-card .sound { font-size: 0.75em; }
  .info-box { padding: 15px; font-size: 0.9em; margin: 10px auto; }
  .example-item { padding: 15px; min-width: 120px; }
  .example-item .dev { font-size: 1.8em; }
  .dense-slide .section-header { font-size: 1.8em; }
  .dense-slide .letter-card .dev { font-size: 2em; }
  .exercise-card { padding: 15px; }
  .exercise-card p { font-size: 1em; }
  .exercise-card .options { font-size: 1.2em; letter-spacing: 5px; }
  .answer { font-size: 1.2em; }
}