:root{
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;

  --bg: #f6f7fb;
  --text: #111;
  --card: #fff;
  --border: #e6e8ef;
  --border-2: #d7dbe7;
  --muted: #666;
  --muted2: #444;
  --toolbar-bg: rgba(255,255,255,0.92);
  --shadow: 0 2px 14px rgba(0,0,0,.04);
  --focus: 0 0 0 3px rgba(138,162,255,.25);
  --primary: #6f88ff;

  --opt-bg: #fafbff;

  color-scheme: light;
}

[data-theme="dark"]{
  --bg: #0b0f19;
  --text: #e9ecf1;
  --card: #111827;
  --border: #243046;
  --border-2: #2a3a55;
  --muted: #a7b0c0;
  --muted2: #c5ccda;
  --toolbar-bg: rgba(17,24,39,0.86);
  --shadow: 0 2px 18px rgba(0,0,0,.35);
  --focus: 0 0 0 3px rgba(111,136,255,.28);
  --primary: #7c93ff;

  --opt-bg: #0f172a;

  color-scheme: dark;
}

/* base */
*{ box-sizing: border-box; }
html, body{ width: 100%; }
body{
  margin: 0;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--text);

  /* iOS safe areas */
  padding-left: env(safe-area-inset-left);
  padding-right: env(safe-area-inset-right);
}

/* layout */
.wrap{
  max-width: 980px;
  margin-left: auto;
  margin-right: auto;
  padding: 18px;
}

.card{
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  box-shadow: var(--shadow);
}

h1{
  margin: 0 0 10px;
  font-size: 20px;
}

p{
  margin: 6px 0 12px;
  color: var(--muted2);
  line-height: 1.4;
}

.muted{
  color: var(--muted);
  font-size: 13px;
}

.grid{
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

@media (min-width: 900px){
  .grid{ grid-template-columns: 1fr 1fr; }
}

/* inputs */
textarea{
  width: 100%;
  min-height: 260px;
  resize: vertical;
  border-radius: 12px;
  border: 1px solid var(--border-2);
  padding: 12px;
  font-size: 16px; /* prevents iOS zoom */
  line-height: 1.5;
  outline: none;
  background: var(--card);
  color: var(--text);
}

@media (min-width: 900px){
  textarea{ min-height: 320px; }  /* restore larger desktop boxes */
}

textarea:focus{
  border-color: var(--primary);
  box-shadow: var(--focus);
}

/* controls */
.controls{
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.controls > *{ margin: 0; }

.btn{
  border: 1px solid var(--border-2);
  background: var(--card);
  color: var(--text);
  padding: 12px 14px;
  border-radius: 14px;
  cursor: pointer;
  font-size: 16px;
  min-height: 44px;
}

.btn.primary{
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
}

.btn:active{ transform: translateY(1px); }

.opt{
  display: inline-flex;
  gap: 8px;
  align-items: center;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--opt-bg);
  color: var(--text);
  min-height: 44px;
}

.status{
  color: #2b6;
  font-size: 13px;
  min-height: 18px;
}

/* toolbar */
.toolbar{
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--toolbar-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 10px;
  margin-bottom: 12px;
}

/* small phones */
@media (max-width: 520px){
  .wrap{ padding: 12px; }
  .card{ padding: 12px; }
  textarea{ min-height: 36vh; }
  h1{ font-size: 18px; }
  .muted{ font-size: 12px; }
  #btnConvert{ width: 100%; }
}

/* dark scrollbar */
[data-theme="dark"] textarea::-webkit-scrollbar{ width: 10px; }
[data-theme="dark"] textarea::-webkit-scrollbar-thumb{ background: #2a3a55; border-radius: 10px; }

@media (max-width: 520px){
  /* overall typography */
  body{ font-size: 18px; }

  /* labels / helper text */
  p{ font-size: 16px; }
  .muted{ font-size: 14px; }

  /* buttons + toggles */
  .btn{ font-size: 17px; }
  .opt{ font-size: 16px; }

  /* textareas */
  textarea{ font-size: 18px; line-height: 1.6; }
}