:root { 
    --yellow: #ffc107; 
}

body { 
    background-color: #050505; 
    color: #e0e0e0; 
    font-family: 'Inter', sans-serif; 
    overflow-x: hidden; 
}

h1, h2, h3, .nav-font { 
    font-family: 'Oxanium', sans-serif; 
}

.glass { 
    background: rgba(255, 255, 255, 0.02); 
    backdrop-filter: blur(12px); 
    border: 1px solid rgba(255, 255, 255, 0.05); 
}

/* Thumbnail Effects */
.thumb-container { 
    position: relative; 
    overflow: hidden; 
    border-radius: 1rem; 
    border: 1px solid rgba(255, 255, 255, 0.1); 
}

.thumb-img { 
    transition: transform 0.5s ease, filter 0.5s ease; 
    width: 100%; 
    height: 100%; 
    object-fit: cover; 
}

.lesson-card:hover .thumb-img { 
    transform: scale(1.1); 
    filter: brightness(1.2); 
}

.lesson-card:hover { 
    border-color: var(--yellow); 
    box-shadow: 0 0 20px rgba(255, 193, 7, 0.1); 
}

.filter-btn.active { 
    background: var(--yellow); 
    color: black; 
    box-shadow: 0 0 15px var(--yellow); 
    border-color: var(--yellow); 
}

/* Play Icon Overlay */
.play-overlay { 
    position: absolute; 
    inset: 0; 
    display: flex; 
    align-items: center; 
    justify-content: center; 
    background: rgba(0,0,0,0.4); 
    opacity: 0; 
    transition: opacity 0.3s; 
    z-index: 10;
}

.lesson-card:hover .play-overlay { 
    opacity: 1; 
}

.neon-yellow { 
    text-shadow: 0 0 10px rgba(255, 193, 7, 0.7); 
}

.neon-border { 
    border: 1px solid rgba(255, 193, 7, 0.3); 
    box-shadow: 0 0 15px rgba(255, 193, 7, 0.1); 
}

.neon-border:hover { 
    border-color: var(--ampharos-yellow); 
    box-shadow: 0 0 20px rgba(255, 193, 7, 0.3); 
    transition: all 0.4s; 
}

header ul li a:hover {
    text-shadow: 0 0 10px rgba(255, 193, 7, 0.5);
}
.bg-grid {
    background-image: linear-gradient(rgba(255, 193, 7, 0.05) 1px, transparent 1px), 
                      linear-gradient(90deg, rgba(255, 193, 7, 0.05) 1px, transparent 1px);
    background-size: 50px 50px;
}

.apostila{
    background-image: url(../images/apostila.png);
    background-size: contain;
    background-repeat: no-repeat;
}

.manual{
    background-image: url(../images/manual.png);
    background-size: contain;
    background-repeat: no-repeat;}
.abc {
  position: relative;
  text-decoration: none;
  color: #000;
}

.abc::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 100%;
  height: 2px;
  background-color: currentColor;

  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}

.abc:hover::after {
  transform: scaleX(1);
}