* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Inter", sans-serif;
}

body {
  background: #0f172a;
  color: #e2e8f0;
  overflow-x: hidden;
}

/* HERO */
.back-btn {
  position: absolute;
  top: 30px;
  left: 40px;
  text-decoration: none;
  color: #94a3b8;
  font-weight: 600;
  transition: 0.3s;
  padding: 8px 16px;
  border-radius: 30px;
  background: rgba(255, 255, 255, 0.05);
  backdrop-filter: blur(10px);
}

.back-btn:hover {
  color: #38bdf8;
  transform: translateX(-5px);
  background: rgba(56, 189, 248, 0.1);
}

.hero {
  padding: 120px 10%;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(90deg, #38bdf8, #6366f1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  margin-top: 1rem;
  color: #94a3b8;
  font-size: 1.1rem;
}

/* GRID */

.systems-grid {
  padding: 60px 10%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

/* CARD */

.system-card {
  position: relative;
  background: #1e293b;
  padding: 2rem;
  border-radius: 24px;
  transition: 0.4s ease;
  overflow: hidden;
  opacity: 0;
  transform: translateY(40px);
}

.system-card.visible {
  opacity: 1;
  transform: translateY(0);
  transition: 0.8s ease;
}

.system-card:hover {
  transform: translateY(-12px);
  box-shadow: 0 25px 60px rgba(56, 189, 248, 0.2);
}

.system-card h3 {
  font-size: 1.3rem;
  font-weight: 700;
}

.system-card p {
  margin-top: 0.5rem;
  color: #94a3b8;
  font-size: 0.95rem;
}

/* IMPACT RING */

.ring-container {
  margin-top: 2rem;
  display: flex;
  justify-content: center;
}

.ring {
  --percent: 0;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: conic-gradient(#38bdf8 calc(var(--percent) * 1%), #0f172a 0%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 1.4rem;
  transition: background 1.5s ease;
  position: relative;
}

.ring::after {
  content: "";
  position: absolute;
  width: 85px;
  height: 85px;
  background: #1e293b;
  border-radius: 50%;
}

.ring span {
  position: relative;
  z-index: 2;
}

/* HOVER EFFECT */

.system-card:hover .ring {
  transform: scale(1.1);
}

/* FOOTER */

.footer {
  padding: 80px 10%;
  text-align: center;
  color: #64748b;
  font-size: 0.9rem;
}