* {
  box-sizing: border-box;
}
body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background: #121212;
  color: #eee;
  min-height: 100vh;
}
header {
  background: #1f1f1f;
  padding: 1rem 2rem;
  text-align: center;
  font-weight: 700;
  font-size: 1.8rem;
  letter-spacing: 2px;
  border-bottom: 3px solid #4caf50;
}
.tabs {
  display: flex;
  justify-content: center;
  background: #222;
  margin-top: 0;
}
.tab-button {
  padding: 1rem 2rem;
  cursor: pointer;
  background: #222;
  border: none;
  outline: none;
  color: #bbb;
  font-weight: 600;
  transition: background 0.3s, color 0.3s;
  user-select: none;
}
.tab-button:hover {
  background: #333;
}
.tab-button.active {
  background: #4caf50;
  color: white;
  font-weight: 700;
}
main {
  max-width: 700px;
  margin: 2rem auto;
  background: #1b1b1b;
  border-radius: 8px;
  padding: 2rem;
  box-shadow: 0 0 10px #4caf50bb;
}
.section {
  display: none;
}
.section.active {
  display: block;
}
label {
  display: block;
  margin: 1rem 0 0.3rem;
  font-weight: 600;
  font-size: 0.9rem;
}
input[type="file"],
select,
textarea,
input[type="text"] {
  width: 100%;
  padding: 0.6rem 0.8rem;
  border-radius: 4px;
  border: none;
  font-size: 1rem;
  margin-bottom: 0.8rem;
  background: #2b2b2b;
  color: #eee;
  transition: box-shadow 0.3s;
}
input[type="file"]::-webkit-file-upload-button {
  cursor: pointer;
  background: #4caf50;
  border: none;
  padding: 0.4rem 0.9rem;
  color: white;
  border-radius: 4px;
  font-weight: 600;
  transition: background 0.3s;
}
input[type="file"]::-webkit-file-upload-button:hover {
  background: #388e3c;
}
textarea {
  resize: vertical;
  min-height: 80px;
}
button {
  background: #4caf50;
  color: white;
  border: none;
  padding: 0.7rem 2rem;
  font-size: 1.1rem;
  border-radius: 6px;
  cursor: pointer;
  margin-top: 1rem;
  font-weight: 700;
  letter-spacing: 1px;
  transition: background 0.3s;
}
button:disabled {
  background: #777;
  cursor: default;
}
button:hover:not(:disabled) {
  background: #388e3c;
}
a.download-link {
  display: none;
  margin-top: 1rem;
  text-decoration: none;
  color: #4caf50;
  font-weight: 600;
  word-break: break-all;
}
a.download-link:hover {
  text-decoration: underline;
}
.response-text {
  margin-top: 1rem;
  padding: 1rem;
  background: #282828;
  border-radius: 6px;
  white-space: pre-wrap;
}
/* Loader */
#fullscreenLoader {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(18, 18, 18, 0.85);
  z-index: 9999;
  justify-content: center;
  align-items: center;
}
.lds-ring {
  display: inline-block;
  position: relative;
  width: 80px;
  height: 80px;
}
.lds-ring div {
  box-sizing: border-box;
  display: block;
  position: absolute;
  width: 64px;
  height: 64px;
  margin: 8px;
  border: 6px solid #4caf50;
  border-radius: 50%;
  animation: lds-ring 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite;
  border-color: #4caf50 transparent transparent transparent;
}
.lds-ring div:nth-child(1) {
  animation-delay: -0.45s;
}
.lds-ring div:nth-child(2) {
  animation-delay: -0.3s;
}
.lds-ring div:nth-child(3) {
  animation-delay: -0.15s;
}
@keyframes lds-ring {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}