* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Inter', sans-serif; }
:root { --nav-color: #1565C0; --button-text-footer: #0a2e52; --extra-color: #ffffff; --default-color: #546e7a; --badge-color: #1976D2; }

/* HERO */
.course-hero { background-size: cover; background-position: center; min-height: 450px; position: relative; display: flex; align-items: center; justify-content: center; }
.hero-overlay { position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: linear-gradient(135deg, rgba(10, 46, 82, 0.9) 0%, rgba(21, 101, 192, 0.8) 100%); display: flex; align-items: center; justify-content: center; }
.course-hero .container { position: relative; z-index: 2; text-align: center; max-width: 800px; }
.hero-title { color: var(--extra-color); font-size: 56px; font-weight: 800; margin-bottom: 15px; text-transform: uppercase; letter-spacing: 2px; }
.hero-subtitle { color: rgba(255, 255, 255, 0.9); font-size: 20px; max-width: 650px; margin: 0 auto; }

/* COMMON TEXT */
.subtitle { font-size: 18px; color: var(--nav-color); font-weight: 600; text-transform: uppercase; letter-spacing: 1px; }
.main-heading { color: var(--button-text-footer); font-weight: 700; font-size: 42px; margin-top: 10px; margin-bottom: 15px; }

/* TOPIC CARDS (Base Style) */
.topic-card { background: var(--extra-color); border-radius: 16px; padding: 30px 20px; text-align: center; box-shadow: 0 5px 15px rgba(0,0,0,0.06); border: 1px solid #e0e0e0; transition: all 0.4s ease; position: relative; overflow: hidden; height: 100%; }
.topic-card::before { content: ''; position: absolute; top: 0; left: 0; width: 0; height: 4px; background: linear-gradient(90deg, var(--nav-color), var(--badge-color)); transition: width 0.5s ease-in-out; z-index: 2; }
.topic-card:hover::before { width: 100%; }
.topic-card:hover { transform: translateY(-10px); box-shadow: 0 15px 30px rgba(21, 101, 192, 0.15); }

.topic-icon-box { width: 70px; height: 70px; border-radius: 50%; background-color: rgba(21, 101, 192, 0.1); display: flex; align-items: center; justify-content: center; margin: 0 auto 20px auto; transition: all 0.3s ease; }
.topic-card:hover .topic-icon-box { background-color: var(--nav-color); box-shadow: 0 0 20px rgba(21, 101, 192, 0.3); }
.topic-icon { font-size: 28px; color: var(--nav-color); transition: color 0.3s ease; }
.topic-card:hover .topic-icon { color: #fff; }

.topic-title { font-weight: 700; color: var(--button-text-footer); margin-bottom: 10px; font-size: 1.2rem; }
.topic-desc { color: var(--default-color); font-size: 0.95rem; line-height: 1.6; text-align: justify; }

/* LARGE TOPIC CARDS & OUTLINE (Frontend / Backend) */
.topic-card-large {
  padding: 40px 35px;
}

.outline-section {
  margin-top: 25px;
  padding-top: 25px;
  border-top: 1px solid #e0e0e0;
}

.outline-heading {
  font-weight: 700;
  color: var(--nav-color);
  font-size: 1rem;
  margin-bottom: 18px;
  text-transform: uppercase;
  letter-spacing: 1px;
  text-align: center;
}

.outline-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px 20px;
}

.outline-list li {
  display: flex;
  align-items: center;
  padding: 10px 15px;
  color: var(--default-color);
  font-size: 0.95rem;
  font-weight: 500;
  background: #f8fafc;
  border-radius: 10px;
  border: 1px solid #eef2f5;
  transition: all 0.3s ease;
}

.outline-list li i {
  color: var(--nav-color);
  font-size: 1.15rem;
  margin-right: 12px;
  width: 24px;
  text-align: center;
  transition: color 0.3s ease;
}

.outline-list li:hover {
  background: var(--nav-color);
  border-color: var(--nav-color);
  transform: translateX(5px);
}

.outline-list li:hover i,
.outline-list li:hover span {
  color: #fff;
}

.outline-list li span {
  transition: color 0.3s ease;
}

/* CTA SECTION */
.cta-text { color: var(--button-text-footer); font-weight: 700; font-size: 1.8rem; margin-bottom: 10px; }
.btn-glow { padding: 14px 35px; background: linear-gradient(135deg, var(--nav-color), var(--badge-color)); color: #fff; border-radius: 50px; text-decoration: none; font-weight: 700; box-shadow: 0 0 20px rgba(21, 101, 192, 0.6); transition: all 0.3s ease; border: none; display: inline-block; }
.btn-glow:hover { transform: translateY(-3px); box-shadow: 0 0 30px rgba(21, 101, 192, 0.8); color: #fff; }

/* Responsive */
@media (max-width: 768px) {
  .hero-title { font-size: 36px; }
  .main-heading { font-size: 32px; }
  .cta-text { font-size: 1.4rem; }
  
  /* Large Cards Responsive */
  .topic-card-large { padding: 30px 20px; }
  .outline-list { grid-template-columns: 1fr; }
}