body {
  background: linear-gradient(135deg, #1a2a6c, #b21f1f, #fdbb2d);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  font-family: 'Inter', sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.sms-box {
  background: rgba(255, 255, 255, 0.12);
  padding: 45px 40px 50px 40px;
  border-radius: 28px;
  width: 100%;
  max-width: 430px;
  box-shadow: 0 10px 40px 0 rgba(31, 38, 135, 0.42),
              0 0 0 1.5px rgba(255, 255, 255, 0.22);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1.5px solid rgba(255, 255, 255, 0.35);
  color: #fff;
  text-align: center;
  user-select: none;
}

.sms-box h2 {
  font-weight: 800;
  font-size: 2rem;
  margin-bottom: 30px;
  letter-spacing: 1.5px;
  text-shadow: 0 3px 8px rgba(0, 0, 0, 0.38);
}

input,
textarea {
  display: block;
  width: 90%;
  margin: 0 auto 22px auto;
  padding: 16px 20px;
  border: none;
  border-radius: 14px;
  font-size: 17px;
  outline: none;
  background: rgba(255, 255, 255, 0.18);
  color: #fff;
  box-shadow: inset 0 4px 10px rgba(0, 0, 0, 0.3);
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
  resize: none;
  font-weight: 500;
  letter-spacing: 0.03em;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.25);
}

input::placeholder,
textarea::placeholder {
  color: #d7d7d7;
  font-style: italic;
}

input:focus,
textarea:focus {
  background: rgba(255, 255, 255, 0.38);
  box-shadow: 0 0 14px #00c6ff;
  color: #fff;
  font-weight: 600;
  text-shadow: 0 0 5px #00c6ff;
}

button {
  width: 90%;
  margin: 0 auto;
  padding: 16px 0;
  border: none;
  border-radius: 14px;
  background: linear-gradient(90deg, #00d4ff, #005dbf);
  color: #fff;
  font-size: 19px;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 8px 22px rgba(0, 93, 191, 0.75);
  transition: background 0.4s ease, box-shadow 0.4s ease;
  display: block;
  user-select: none;
  letter-spacing: 0.06em;
  text-shadow: 0 0 6px rgba(0, 214, 255, 0.8);
}

button:hover,
button:focus {
  background: linear-gradient(90deg, #005dbf, #00d4ff);
  box-shadow: 0 10px 30px rgba(0, 212, 255, 0.9);
  outline: none;
  text-shadow: 0 0 9px rgba(0, 255, 255, 1);
}

.loading {
  margin-top: 20px;
  font-size: 1.1rem;
  font-weight: 700;
  color: #00d4ff;
  text-align: center;
  display: none;
  user-select: none;
  text-shadow: 0 0 7px #00d4ff;
}

.developer-credit {
  margin-top: 18px;
  font-size: 14px;
  font-weight: 600;
  color: #a0cfff;
  letter-spacing: 0.05em;
  text-shadow: 0 0 5px rgba(160, 207, 255, 0.7);
  user-select: none;
  font-style: italic;
}