/* ===== Base ===== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: #0f172a; /* dark navy */
  color: #e5e7eb; /* light gray */
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

/* ===== Container ===== */
main {
  background: #111827;
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  padding: 28px;
  max-width: 500px;
  width: 100%;
  box-shadow: 0 8px 30px rgba(0, 0, 0, 0.4);
}

/* ===== Title ===== */
h1 {
  text-align: center;
  font-size: 1.8rem;
  margin-bottom: 20px;
  color: #f8fafc;
}

/* ===== Form ===== */
form {
  display: grid;
  gap: 14px;
}

label {
  font-size: 0.95rem;
  color: #cbd5e1;
}

input[type="text"] {
  padding: 12px 14px;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 12px;
  background: rgba(17, 24, 39, 0.7);
  color: #f8fafc;
  font-size: 1rem;
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
input[type="text"]:focus {
  border-color: #22d3ee;
  box-shadow: 0 0 0 4px rgba(34, 211, 238, 0.3);
}

/* ===== Buttons ===== */
.phone-footer {
  display: flex;
  gap: 10px;
  justify-content: center;
}

.btn-styles {
  flex: 1;
  padding: 10px 16px;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  transition: background 0.2s ease, transform 0.08s ease;
}
#check-btn {
  background: linear-gradient(135deg, #22d3ee, #06b6d4);
  color: #001219;
}
#check-btn:hover {
  filter: brightness(1.08);
}
#check-btn:active {
  transform: scale(0.97);
}

#clear-btn {
  background: #ef4444;
  color: white;
}
#clear-btn:hover {
  background: #dc2626;
}
#clear-btn:active {
  transform: scale(0.97);
}

/* ===== Results ===== */
#results-div {
  margin-top: 14px;
  font-size: 1.05rem;
  text-align: center;
  font-weight: 600;
}