/* ================================================================
   Nerdania Photo — Dark Neon Glassmorphism
   Mobile-first responsive design
   ================================================================ */

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

:root {
  --bg: #0a0e1a;
  --bg-elevated: #0f1424;
  --bg-card: rgba(255,255,255,0.025);
  --bg-glass: rgba(15,20,36,0.75);
  --border: rgba(255,255,255,0.06);
  --border-hover: rgba(255,255,255,0.14);
  --border-glow: rgba(99,102,241,0.3);
  --text-primary: #eef2ff;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #6366f1;
  --accent-hover: #818cf8;
  --accent-glow: rgba(99,102,241,0.15);
  --cyan: #22d3ee;
  --cyan-glow: rgba(34,211,238,0.12);
  --green: #34d399;
  --green-glow: rgba(52,211,153,0.12);
  --purple: #a855f7;
  --radius: 16px;
  --radius-sm: 10px;
  --transition: 0.25s cubic-bezier(0.4,0,0.2,1);
}

html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

/* ===== HEADER ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(20px) saturate(1.8);
  background: var(--bg-glass);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.875rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
}
.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--text-primary);
}
.logo-icon { font-size: 1.75rem; }
.logo-text {
  font-size: 1.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.logo-tag {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ===== MAIN ===== */
.main { flex: 1; max-width: 960px; width: 100%; margin: 0 auto; padding: 2rem 1.25rem; }

/* ===== SECTIONS ===== */
.section { display: none; }
.section.active { display: block; animation: fadeIn 0.4s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }

/* ===== UPLOAD ZONE ===== */
.upload-hero {
  text-align: center;
  margin-bottom: 2rem;
}
.upload-hero h1 {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 0.75rem;
}
.upload-hero h1 .gradient {
  background: linear-gradient(135deg, var(--accent), var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.upload-hero p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.6;
}

.drop-zone {
  border: 2px dashed var(--border-hover);
  border-radius: var(--radius);
  padding: 3.5rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: var(--transition);
  background: var(--bg-card);
  position: relative;
  overflow: hidden;
}
.drop-zone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, var(--accent-glow), transparent 70%);
  opacity: 0;
  transition: var(--transition);
}
.drop-zone:hover, .drop-zone.drag-over {
  border-color: var(--accent);
  background: rgba(99,102,241,0.04);
}
.drop-zone:hover::before, .drop-zone.drag-over::before { opacity: 1; }

.drop-icon {
  font-size: 3.5rem;
  margin-bottom: 1rem;
  display: block;
  position: relative;
}
.drop-title {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  position: relative;
}
.drop-subtitle {
  color: var(--text-muted);
  font-size: 0.85rem;
  position: relative;
}
.drop-subtitle .accent { color: var(--accent); font-weight: 600; }

/* Features */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 2.5rem;
}
.feature {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
  text-align: center;
  transition: var(--transition);
}
.feature:hover { border-color: var(--border-hover); background: rgba(255,255,255,0.035); }
.feature-icon { font-size: 1.75rem; margin-bottom: 0.5rem; display: block; }
.feature-title { font-size: 0.85rem; font-weight: 600; margin-bottom: 0.25rem; }
.feature-desc { font-size: 0.75rem; color: var(--text-muted); }

/* ===== PROGRESS ===== */
.progress-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 3rem 2rem;
  text-align: center;
  max-width: 520px;
  margin: 3rem auto;
}
.progress-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 2rem;
}
.progress-bar-wrap {
  height: 12px;
  background: rgba(255,255,255,0.05);
  border-radius: 6px;
  overflow: hidden;
  margin-bottom: 1.25rem;
  position: relative;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--cyan));
  border-radius: 6px;
  transition: width 0.4s ease;
  position: relative;
}
.progress-fill::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  animation: shimmer 1.5s infinite;
}
@keyframes shimmer { 0% { transform: translateX(-100%); } 100% { transform: translateX(100%); } }

.progress-percent {
  font-family: 'JetBrains Mono', monospace;
  font-size: 2.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.5rem;
}
.progress-label {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ===== RESULT ===== */
.result-header {
  text-align: center;
  margin-bottom: 2rem;
}
.result-header h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 0.25rem;
}
.result-header .badge {
  display: inline-block;
  background: var(--green-glow);
  color: var(--green);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  border: 1px solid rgba(52,211,153,0.2);
}

.comparison {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
  margin-bottom: 2rem;
}
@media (max-width: 640px) { .comparison { grid-template-columns: 1fr; } }

.photo-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.photo-card.enhanced { border-color: var(--border-glow); }
.photo-label {
  padding: 0.75rem 1rem;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.photo-card.enhanced .photo-label { color: var(--cyan); border-color: rgba(99,102,241,0.15); }
.photo-info { font-family: 'JetBrains Mono', monospace; font-size: 0.7rem; color: var(--text-muted); }
.photo-card img {
  width: 100%;
  display: block;
  object-fit: contain;
  max-height: 400px;
  background: #000;
}

/* Actions */
.actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 1.75rem;
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), #4f46e5);
  color: white;
  box-shadow: 0 4px 20px var(--accent-glow);
}
.btn-primary:hover { background: linear-gradient(135deg, var(--accent-hover), var(--accent)); transform: translateY(-1px); box-shadow: 0 6px 30px rgba(99,102,241,0.25); }

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-hover);
}
.btn-secondary:hover { border-color: var(--accent); background: rgba(99,102,241,0.06); }

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border);
}
.btn-ghost:hover { color: var(--text-primary); border-color: var(--border-hover); }

/* ===== FOOTER ===== */
.site-footer {
  text-align: center;
  padding: 2rem 1.25rem;
  border-top: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.8rem;
}
.site-footer a { color: var(--accent); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

/* ===== TOAST ===== */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: #ef4444;
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  opacity: 0;
  transition: all 0.3s ease;
  z-index: 1000;
  box-shadow: 0 8px 30px rgba(239,68,68,0.3);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.08); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.15); }

::selection { background: var(--accent); color: white; }

/* ===== HEADER SETTINGS ICON ===== */
.header-inner {
  justify-content: space-between;
}
.btn-icon {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.25rem;
  padding: 0.4rem;
  border-radius: 8px;
  transition: var(--transition);
  line-height: 1;
  color: var(--text-secondary);
}
.btn-icon:hover { background: rgba(255,255,255,0.06); }

/* ===== PROMPT SECTION ===== */
.prompt-section {
  margin-top: 1.75rem;
}
.prompt-section-title {
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}
.prompt-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 0.6rem;
}
.prompt-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
  padding: 0.85rem 0.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  font-family: inherit;
  color: var(--text-secondary);
}
.prompt-btn:hover {
  border-color: var(--border-hover);
  background: rgba(255,255,255,0.04);
  color: var(--text-primary);
}
.prompt-btn.active {
  border-color: var(--accent);
  background: var(--accent-glow);
  color: var(--text-primary);
  box-shadow: 0 0 12px var(--accent-glow);
}
.prompt-btn-icon { font-size: 1.5rem; }
.prompt-btn-label { font-size: 0.75rem; font-weight: 600; text-align: center; }

/* ===== CUSTOM PROMPT ===== */
.custom-prompt-wrap {
  margin-top: 1.25rem;
}
.custom-prompt-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
}
.custom-prompt {
  width: 100%;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.75rem 1rem;
  font-family: inherit;
  font-size: 0.9rem;
  color: var(--text-primary);
  resize: vertical;
  transition: var(--transition);
  min-height: 70px;
}
.custom-prompt::placeholder { color: var(--text-muted); }
.custom-prompt:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-glow);
}

/* ===== QUALITY ROW ===== */
.quality-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-top: 1rem;
}
.quality-label {
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--text-muted);
}
.quality-select {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.5rem 0.75rem;
  font-family: inherit;
  font-size: 0.85rem;
  color: var(--text-primary);
  cursor: pointer;
  transition: var(--transition);
}
.quality-select:focus {
  outline: none;
  border-color: var(--accent);
}

/* ===== API HINT BANNER ===== */
.api-hint {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: rgba(234,179,8,0.06);
  border: 1px solid rgba(234,179,8,0.2);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: #eab308;
  text-align: center;
}
.api-hint a { color: var(--accent); text-decoration: underline; cursor: pointer; }

/* ===== SETTINGS MODAL ===== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  backdrop-filter: blur(6px);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}
.modal-overlay[hidden] { display: none; }
.modal {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  width: 100%;
  max-width: 440px;
  overflow: hidden;
  animation: fadeIn 0.25s ease;
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
}
.modal-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
}
.modal-body {
  padding: 1.25rem;
}
.form-group {
  margin-bottom: 1.25rem;
}
.form-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.input-row {
  display: flex;
  gap: 0.5rem;
}
.form-input {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.85rem;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85rem;
  color: var(--text-primary);
  transition: var(--transition);
}
select.form-input {
  font-family: inherit;
  cursor: pointer;
}
.form-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-glow);
}
.form-input::placeholder { color: var(--text-muted); }
.btn-icon-sm {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0 0.6rem;
  cursor: pointer;
  font-size: 1rem;
  transition: var(--transition);
}
.btn-icon-sm:hover { border-color: var(--border-hover); }
.form-hint {
  margin-top: 0.35rem;
  font-size: 0.75rem;
}
.hint-ok { color: var(--green); }
.hint-warn { color: #eab308; }
.form-actions {
  padding-top: 0.5rem;
}
.form-actions .btn { width: 100%; justify-content: center; }

/* ===== MOBILE RESPONSIVE ===== */
@media (max-width: 768px) {
  html { font-size: 15px; }
  .main { padding: 1.25rem 0.875rem; }
  .header-inner { padding: 0.65rem 0.875rem; }

  .upload-hero { margin-bottom: 1.25rem; }
  .upload-hero p { font-size: 0.95rem; }

  .drop-zone { padding: 2.25rem 1.25rem; }
  .drop-icon { font-size: 2.75rem; margin-bottom: 0.75rem; }
  .drop-title { font-size: 1rem; }
  .drop-subtitle { font-size: 0.8rem; }

  .prompt-grid {
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: 0.5rem;
  }
  .prompt-btn { padding: 0.65rem 0.35rem; }
  .prompt-btn-icon { font-size: 1.25rem; }
  .prompt-btn-label { font-size: 0.7rem; }

  .custom-prompt { min-height: 60px; font-size: 0.85rem; }

  .features { grid-template-columns: repeat(2, 1fr); gap: 0.75rem; margin-top: 1.75rem; }
  .feature { padding: 1rem 0.75rem; }
  .feature-icon { font-size: 1.5rem; }
  .feature-title { font-size: 0.8rem; }
  .feature-desc { font-size: 0.7rem; }

  .progress-card { padding: 2rem 1.25rem; margin: 2rem auto; }
  .progress-percent { font-size: 2rem; }

  .comparison { gap: 0.75rem; }
  .photo-card img { max-height: 280px; }

  .actions { gap: 0.65rem; }
  .btn { padding: 0.75rem 1.25rem; font-size: 0.875rem; }
}

@media (max-width: 480px) {
  html { font-size: 14px; }
  .main { padding: 1rem 0.65rem; }

  .logo-icon { font-size: 1.35rem; }
  .logo-text { font-size: 1.25rem; }

  .drop-zone { padding: 1.75rem 1rem; }
  .drop-icon { font-size: 2.25rem; }

  .prompt-grid { grid-template-columns: repeat(3, 1fr); }

  .features { grid-template-columns: 1fr 1fr; gap: 0.5rem; }

  .progress-card { padding: 1.5rem 1rem; }
  .progress-title { font-size: 1.05rem; }
  .progress-percent { font-size: 1.75rem; }

  .result-header h2 { font-size: 1.2rem; }

  .actions { flex-direction: column; align-items: stretch; }
  .btn { justify-content: center; }
}