:root {
  --nf-bg: #F9FAFB;        /* Background */
  --nf-primary: #2563EB;   /* Bright blue */
  --nf-text: #111827;      /* Text */
  --nf-accent: #10B981;    /* Green */
  --nf-muted: #6B7280;     /* Gray */
  --nf-radius: 12px;
  --nf-shadow: 0 10px 30px rgba(0, 0, 0, 0.06);
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
  margin: 0;
  font-family: Arial, sans-serif;
  color: var(--nf-text);
  background: var(--nf-bg);
}

.nf-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.nf-header {
  background: var(--nf-bg);
  border-bottom: 1px solid var(--nf-muted);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nf-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--nf-text);
}

.nf-logo-icon {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--nf-primary);
  color: white;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nf-logo-text {
  font-weight: 600;
}

.nf-hero {
  padding: 40px 0;
  text-align: center;
}

.nf-hero h1 {
  font-size: 30px;
  margin: 0;
}

.nf-subtitle {
  color: var(--nf-muted);
  margin: 10px 0;
}

.nf-dropzone {
  background: #fff;
  border: 2px dashed var(--nf-muted);
  border-radius: var(--nf-radius);
  min-height: 150px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--nf-shadow);
  cursor: pointer;
  transition: 0.2s;
}

.nf-dropzone:hover {
  border-color: var(--nf-primary);
}

.nf-dropzone:focus {
  box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.2);
}

.nf-drop-inner {
  text-align: center;
}

.nf-file-icon {
  color: var(--nf-primary);
  margin-bottom: 10px;
}

.nf-drop-hint {
  color: var(--nf-muted);
}

.nf-btn {
  display: inline-block;
  padding: 10px 20px;
  border-radius: var(--nf-radius);
  background-color: var(--nf-primary);
  color: #fff;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s;
}

.nf-btn:hover {
  background-color: var(--nf-accent);
}

.nf-btn-accent {
  background-color: var(--nf-accent);
}

.nf-btn-primary {
  background-color: var(--nf-primary);
}

.nf-panel {
  background: #fff;
  border: 1px solid var(--nf-muted);
  padding: 20px;
  border-radius: var(--nf-radius);
  box-shadow: var(--nf-shadow);
}

.nf-hidden {
  display: none;
}

.nf-actions {
  text-align: center;
  margin-top: 20px;
}

.nf-spinner {
  border: 4px solid var(--nf-muted);
  border-top: 4px solid var(--nf-primary);
  border-radius: 50%;
  width: 24px;
  height: 24px;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.nf-footer {
  padding: 20px 0;
  text-align: center;
  color: var(--nf-muted);
  border-top: 1px solid var(--nf-muted);
}

@media (max-width: 768px) {
  .nf-hero h1 {
    font-size: 24px;
  }

  .nf-btn {
    padding: 8px 16px;
  }
}