:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --primary: #0b5fff;
  --primary-dark: #0848c4;
  --success: #0f9d58;
  --border: #d9e2f1;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "Arial", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at 15% 10%, #dce9ff 0%, transparent 35%),
    radial-gradient(circle at 85% 20%, #d7f5ea 0%, transparent 30%),
    var(--bg);
  line-height: 1.55;
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px;
}

.hero {
  background: linear-gradient(120deg, #0b5fff, #1f7aff);
  color: #fff;
  padding: 24px;
  border-radius: 18px;
  box-shadow: 0 16px 40px rgba(11, 95, 255, 0.24);
}

.hero h1 {
  margin: 0 0 10px;
  font-size: 2rem;
}

.hero p {
  margin: 0;
  opacity: 0.96;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
  margin-top: 18px;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
}

.card h2,
.card h3 {
  margin: 0 0 10px;
}

.links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.links li + li {
  margin-top: 10px;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

label {
  display: block;
  font-weight: 600;
  margin: 10px 0 5px;
}

input,
select {
  width: 100%;
  border: 1px solid #c8d5ea;
  border-radius: 10px;
  font-size: 1rem;
  padding: 10px;
}

input[type="checkbox"] {
  width: auto;
  transform: scale(1.15);
  margin-top: 6px;
}

.button {
  margin-top: 12px;
  border: 0;
  background: var(--primary);
  color: #fff;
  border-radius: 10px;
  padding: 10px 14px;
  font-weight: 700;
  cursor: pointer;
}

.button:hover {
  background: var(--primary-dark);
}

.result {
  margin-top: 12px;
  border-left: 4px solid var(--success);
  padding: 10px 12px;
  background: #f1fbf6;
  border-radius: 8px;
}

.muted {
  color: var(--muted);
}

.footer {
  margin: 28px 0 12px;
  color: #5a6b88;
  font-size: 0.95rem;
}

@media (max-width: 900px) {
  .grid {
    grid-template-columns: 1fr;
  }

  .hero h1 {
    font-size: 1.65rem;
  }
}