:root {
  --primary: #FF0000;
  --dark: #000000;
  --offwhite: #F0F0F0;
  --gray-800: #1f2937;
  --gray-700: #374151;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background-color: var(--dark);
  color: var(--offwhite);
  font-family: 'Space Grotesk', sans-serif;
  min-height: 100vh;
  padding: 2rem 0;
  display: flex;
  align-items: center; /* Centrado vertical */
}

.container {
  max-width: 600px;
  margin: 0 auto;
  padding: 0 1.5rem;
  width: 100%;
}

.header {
  text-align: center;
  margin-bottom: 2.5rem;
}

.header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
  letter-spacing: -1px;
}

.header p {
  color: #aaa;
  font-size: 1.1rem;
}

.card {
  background: #111;
  border: 1px solid var(--gray-700);
  border-radius: 16px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}

/* Formulario */
.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  color: #bbb;
  font-size: 0.95rem;
  font-weight: 600;
}

.form-group input {
  width: 100%;
  padding: 0.875rem;
  background: var(--gray-800);
  border: 1px solid var(--gray-700);
  border-radius: 8px;
  color: var(--offwhite);
  font-size: 1rem;
  transition: border-color 0.3s;
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
}

.helper-text {
  display: block;
  margin-top: 0.5rem;
  color: #666;
  font-size: 0.8rem;
}

/* Drag & Drop Zone */
.drop-zone {
  position: relative;
  border: 2px dashed #444;
  border-radius: 12px;
  padding: 2.5rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  background: #1a1a1a;
  color: #ccc;
}

.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--primary);
  background: rgba(255, 0, 0, 0.05);
  color: white;
}

.drop-zone__icon {
  margin: 0 auto 1rem;
  color: #666;
  transition: transform 0.3s ease;
}

.drop-zone:hover .drop-zone__icon {
  color: var(--primary);
  transform: scale(1.1);
}

.drop-zone__input {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  opacity: 0;
  cursor: pointer;
}

/* File Preview */
.file-preview {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: rgba(255, 0, 0, 0.1); /* Tono rojizo sutil */
  padding: 0.75rem 1rem;
  border-radius: 8px;
  border: 1px solid rgba(255, 0, 0, 0.2);
  margin-top: 1rem;
}

.remove-btn {
  background: #444;
  color: white;
  border: none;
  border-radius: 50%;
  width: 24px;
  height: 24px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.3s;
}

.remove-btn:hover {
  background: var(--primary);
}

/* Botón Principal */
.btn {
  width: 100%;
  padding: 1.1rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 8px;
  font-weight: 700;
  font-size: 1.1rem;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 1rem;
}

.btn:hover:not(:disabled) {
  background: #cc0000;
  box-shadow: 0 0 20px rgba(255, 0, 0, 0.4);
  transform: translateY(-2px);
}

.btn:disabled {
  background: #333;
  color: #777;
  cursor: not-allowed;
}

/* Utilidades */
.hidden { display: none !important; }
.mt-3 { margin-top: 0.75rem; }

footer {
  text-align: center;
  color: #555;
  font-size: 0.875rem;
}