/* ===== Reset & Variables ===== */
:root {
  --primary:       #2563eb;
  --primary-h:     #1d4ed8;
  --bg:            #f1f5f9;
  --surface:       #ffffff;
  --border:        #e2e8f0;
  --text:          #1e293b;
  --text-muted:    #64748b;
  --hint:          #d97706;
  --radius:        10px;
  --radius-sm:     6px;
  --shadow:        0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);
  --shadow-lg:     0 4px 16px rgba(0,0,0,.1);
  --transition:    .2s ease;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Hiragino Sans', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

/* ===== Header ===== */
.site-header {
  background: linear-gradient(135deg, var(--primary) 0%, #1e40af 100%);
  color: #fff;
  padding: 1.75rem 1.5rem;
  text-align: center;
  box-shadow: 0 2px 8px rgba(37,99,235,.35);
}
.site-header h1 { font-size: clamp(1.3rem, 4vw, 1.9rem); font-weight: 700; letter-spacing: -.01em; }
.site-header p  { margin-top: .35rem; font-size: .82rem; opacity: .88; }

/* ===== Main Layout ===== */
main { padding: 2rem 1rem 3rem; }

.container {
  max-width: 1120px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  align-items: start;
}

/* ===== Panel ===== */
.panel {
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
}

/* ===== Tabs ===== */
.tabs {
  display: flex;
  border-bottom: 2px solid var(--border);
  margin-bottom: 1.5rem;
  gap: .15rem;
}

.tab {
  flex: 1;
  padding: .55rem .5rem;
  border: none;
  background: none;
  cursor: pointer;
  font-size: .8rem;
  font-weight: 600;
  color: var(--text-muted);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  border-radius: var(--radius-sm) var(--radius-sm) 0 0;
  transition: color var(--transition), background var(--transition);
  white-space: nowrap;
}
.tab:hover  { color: var(--primary); background: #f8fafc; }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }

/* ===== Tab Content ===== */
.tab-content { display: none; }
.tab-content.active { display: block; }

/* ===== Form Fields ===== */
.field { margin-bottom: .9rem; }
.fields-two {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 .75rem;
}

.field label {
  display: block;
  font-size: .8rem;
  font-weight: 600;
  margin-bottom: .3rem;
  color: #374151;
}

.field input[type="text"],
.field input[type="tel"],
.field input[type="email"],
.field textarea,
.field select {
  width: 100%;
  padding: .5rem .75rem;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: .875rem;
  font-family: inherit;
  color: var(--text);
  background: #fafafa;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.field input:focus,
.field textarea:focus,
.field select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,.12);
  background: #fff;
}
.field textarea { resize: vertical; }

/* ===== Hint ===== */
.hint {
  font-size: .72rem;
  color: var(--hint);
  font-weight: 500;
  margin-left: .4rem;
}

/* ===== Options ===== */
.options-section {
  border-top: 1px solid var(--border);
  padding-top: 1.25rem;
  margin-top: 1.25rem;
}
.options-title { font-size: .95rem; font-weight: 700; margin-bottom: 1rem; }

.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .75rem;
  margin-bottom: .75rem;
}

/* ===== Color Picker ===== */
.color-wrap {
  display: flex;
  align-items: center;
  gap: .6rem;
}
.color-wrap input[type="color"] {
  width: 40px;
  height: 36px;
  padding: 2px 3px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  background: none;
}
.color-hex {
  font-size: .8rem;
  color: var(--text-muted);
  font-family: 'Courier New', monospace;
}

/* ===== Logo Controls ===== */
.logo-controls {
  display: flex;
  align-items: center;
  gap: .75rem;
}
.logo-controls input[type="file"] { flex: 1; font-size: .8rem; }
.logo-name { font-size: .75rem; color: var(--text-muted); margin-top: .3rem; }

.btn-sm {
  padding: .35rem .7rem;
  font-size: .78rem;
  border: 1.5px solid var(--border);
  background: #fff;
  border-radius: var(--radius-sm);
  cursor: pointer;
  white-space: nowrap;
  color: var(--text);
  transition: background var(--transition);
}
.btn-sm:hover { background: #f1f5f9; }

/* ===== Primary Button ===== */
.btn-primary {
  width: 100%;
  margin-top: 1.5rem;
  padding: .8rem;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 2px 8px rgba(37,99,235,.3);
}
.btn-primary:hover  { background: var(--primary-h); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(37,99,235,.35); }
.btn-primary:active { transform: translateY(0); }

/* ===== Preview Panel ===== */
.preview-panel h2 { font-size: .95rem; font-weight: 700; margin-bottom: 1rem; }

.preview-box {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 300px;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fafafa;
  position: relative;
}

#qr-preview canvas,
#qr-preview svg {
  max-width: 100%;
  height: auto;
  display: block;
}

.placeholder-text {
  text-align: center;
  color: var(--text-muted);
  font-size: .875rem;
  padding: 1.5rem;
  line-height: 1.8;
}

/* ===== Download Buttons ===== */
.download-buttons {
  display: flex;
  gap: .75rem;
  margin-top: 1rem;
}
.btn-download {
  flex: 1;
  padding: .6rem .5rem;
  border: 2px solid var(--primary);
  background: #fff;
  color: var(--primary);
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: .82rem;
  cursor: pointer;
  transition: all var(--transition);
}
.btn-download:hover { background: var(--primary); color: #fff; }

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: #1e293b;
  color: #fff;
  padding: .65rem 1.5rem;
  border-radius: 100px;
  font-size: .82rem;
  opacity: 0;
  pointer-events: none;
  transition: all .3s cubic-bezier(.34,1.56,.64,1);
  z-index: 9999;
  white-space: nowrap;
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* ===== Footer ===== */
footer {
  text-align: center;
  padding: 1.5rem 1rem 2rem;
  font-size: .75rem;
  color: var(--text-muted);
}
footer a { color: var(--text-muted); text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* ===== Responsive ===== */
@media (max-width: 800px) {
  .container { grid-template-columns: 1fr; }
  .options-grid { grid-template-columns: 1fr 1fr; }
  .fields-two { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .tabs { gap: 0; }
  .tab { font-size: .72rem; padding: .5rem .3rem; }
  .options-grid { grid-template-columns: 1fr; }
}