body {
  background-color: #0d1117;
  color: #c9d1d9;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
}
.login-wrapper {
  width: 100%;
  max-width: 420px;
  padding: 20px;
}
.login-box {
  background-color: #161b22;
  padding: 30px 40px;
  border-radius: 12px;
  border: 1px solid #30363d;
}
h1 {
  font-size: 1.8em;
  text-align: center;
  margin-top: 0;
  margin-bottom: 10px;
  color: #f0f6fc;
}
.subtitle {
  text-align: center;
  color: #8b949e;
  margin-bottom: 30px;
}
.form-group {
  margin-bottom: 20px;
}
.form-group label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
}
input[type="tel"],
input[type="text"] {
  width: 100%;
  padding: 12px;
  background-color: #0d1117;
  border: 1px solid #30363d;
  border-radius: 8px;
  color: #c9d1d9;
  font-size: 1.2em;
  text-align: center;
  box-sizing: border-box;
}
input:focus {
  outline: none;
  border-color: #58a6ff;
  box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.3);
}
button {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 8px;
  background-color: #238636;
  color: white;
  font-size: 1.1em;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.2s;
}
button:hover:not(:disabled) {
  background-color: #2ea043;
}
button:disabled {
  background-color: #30363d;
  cursor: not-allowed;
}
.error-msg {
  color: #ff99a1;
  text-align: center;
  margin-top: 15px;
  min-height: 20px;
}
.otp-inputs {
  display: flex;
  justify-content: space-between;
  gap: 10px;
}
.otp-input {
  width: 50px;
  height: 60px;
  font-size: 2em;
  text-align: center;
}
.ref-code {
  text-align: center;
  font-size: 0.9em;
  color: #8b949e;
  background-color: #0d1117;
  padding: 5px;
  border-radius: 4px;
  margin-bottom: 20px;
}
.otp-footer {
  display: flex;
  justify-content: space-between;
  margin-top: 20px;
  font-size: 0.9em;
}
.otp-footer a {
  color: #58a6ff;
  text-decoration: none;
}
.otp-footer span {
  color: #8b949e;
}
/* สำหรับซ่อน label ที่ใช้เพื่อ accessibility เท่านั้น */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}
.loader {
    width: 16px;
    height: 16px;
    border: 2px solid #fff;
    border-bottom-color: transparent;
    border-radius: 50%;
    display: inline-block;
    box-sizing: border-box;
    animation: rotation 1s linear infinite;
    margin-right: 8px;
    vertical-align: middle;
}
@keyframes rotation {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}