/* =========================
   RESET & BASE
========================= */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
  background: #f5f6f8;
  color: #1f2937;
  line-height: 1.6;
}

/* =========================
   LAYOUT
========================= */
.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 1rem;
}

.hidden {
  display: none !important;
}

/* =========================
   TYPOGRAPHY
========================= */
h1 {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  text-align: center;
  margin-bottom: 0.5rem;
  color: #2563eb;
}

h2 {
  font-size: 1.4rem;
  margin-bottom: 0.6rem;
}

h3 {
  font-size: 1.1rem;
  margin-bottom: 0.4rem;
}

.subtitle {
  text-align: center;
  color: #6b7280;
  margin-bottom: 1.5rem;
}

/* =========================
   CARDS
========================= */
.card {
  background: #ffffff;
  border-radius: 10px;
  padding: 1.2rem;
  margin-bottom: 1rem;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.06);
}

/* =========================
   UPLOAD AREA
========================= */
.upload {
  border: 2px dashed #2563eb;
  text-align: center;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
}

.upload:hover {
  background: #f0f6ff;
}

.upload label {
  display: block;
  cursor: pointer;
}

.upload p {
  font-size: 1rem;
  color: #374151;
}

.upload input {
  display: none;
}

/* =========================
   FILE LIST
========================= */
.file-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.6rem 0;
  border-bottom: 1px solid #e5e7eb;
  font-size: 0.95rem;
}

.file-item:last-child {
  border-bottom: none;
}

/* =========================
   BUTTONS
========================= */
button {
  font-family: inherit;
}

.primary {
  width: 100%;
  padding: 0.85rem;
  background: #2563eb;
  color: #ffffff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

.primary:hover {
  background: #1d4ed8;
}

.primary:active {
  transform: scale(0.98);
}

/* =========================
   PROGRESS BAR
========================= */
.progress {
  height: 8px;
  background: #e5e7eb;
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 1rem;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: #2563eb;
  transition: width 0.3s ease;
}

/* =========================
   PREVIEW
========================= */
#preview iframe {
  width: 100%;
  height: 450px;
  border: 1px solid #e5e7eb;
  border-radius: 8px;
  background: #ffffff;
}

/* =========================
   SEO CONTENT
========================= */
.seo-content {
  margin-top: 2rem;
}

.seo-content p {
  margin-bottom: 0.8rem;
  color: #374151;
}

.seo-content ul {
  padding-left: 1.3rem;
}

.seo-content li {
  margin-bottom: 0.4rem;
}

/* =========================
   HEADER & FOOTER
========================= */
#header,
#footer {
  width: 100%;
}

/* =========================
   RESPONSIVE
========================= */
@media (max-width: 768px) {
  #preview iframe {
    height: 320px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0.8rem;
  }

  h1 {
    font-size: 1.6rem;
  }

  .primary {
    padding: 0.75rem;
  }
}