:root{
  --ink:#111014;
  --paper:#F6F5F1;
  --paper-2:#EDEBE4;
  --accent:#FF5A1F;
  --accent-2:#1F6FFF;
  --line:#DAD7CC;
  --mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;
  --serif: 'Fraunces', Georgia, serif;
}
html.dark{
  --ink:#F2F1EC;
  --paper:#17161A;
  --paper-2:#201F24;
  --line:#33323A;
  --accent:#FF6A32;
  --accent-2:#4C8CFF;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{
  background:var(--paper);
  color:var(--ink);
  font-family:var(--mono);
  -webkit-font-smoothing:antialiased;
  display:flex;
  flex-direction:column;
  min-height:100vh;
  transition:background .2s ease, color .2s ease;
}

header{
  padding:clamp(16px,3vw,28px) clamp(16px,4vw,40px);
  display:flex;
  justify-content:space-between;
  align-items:center;
  border-bottom:1px solid var(--line);
  gap:12px;
  flex-wrap:wrap;
}
.logo{
  font-family:var(--serif);
  font-weight:700;
  font-size:clamp(20px,3vw,26px);
  letter-spacing:-0.02em;
  display:flex;
  align-items:center;
  gap:8px;
}
.logo .dot{
  width:10px;height:10px;background:var(--accent);border-radius:2px;
  transform:rotate(45deg);
  flex-shrink:0;
}
.header-right{display:flex;align-items:center;gap:14px;flex-wrap:wrap}
.tag{
  font-size:11px;
  text-transform:uppercase;
  letter-spacing:0.12em;
  color:#6b6a66;
}
.icon-btn{
  width:32px;height:32px;
  border-radius:8px;
  border:1px solid var(--line);
  background:transparent;
  color:var(--ink);
  cursor:pointer;
  font-size:14px;
  display:flex;align-items:center;justify-content:center;
}

main{
  flex:1;
  display:flex;
  flex-direction:column;
  align-items:center;
  padding:clamp(20px,5vw,60px) clamp(16px,4vw,40px) 40px;
  width:100%;
}

.hero{
  text-align:center;
  max-width:640px;
  margin-bottom:clamp(24px,4vw,40px);
}
.hero h1{
  font-family:var(--serif);
  font-weight:700;
  font-size:clamp(28px,5.5vw,48px);
  line-height:1.05;
  letter-spacing:-0.02em;
}
.hero h1 em{
  font-style:italic;
  color:var(--accent);
}
.hero p{
  margin-top:12px;
  font-size:clamp(13px,1.6vw,15px);
  color:#5c5b57;
  line-height:1.5;
}

.layout{
  width:100%;
  max-width:760px;
  display:flex;
  flex-direction:column;
  gap:16px;
}

/* off-canvas sidebar */
.sidebar{
  position:fixed;
  top:0;right:0;bottom:0;
  width:min(320px,88vw);
  background:#fff;
  border-left:1px solid var(--line);
  padding:20px;
  transform:translateX(100%);
  transition:transform .25s ease;
  z-index:70;
  overflow-y:auto;
  display:flex;
  flex-direction:column;
}
html.dark .sidebar{background:var(--paper-2)}
.sidebar.show{transform:translateX(0)}
.sidebar-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}
.sidebar-overlay{
  display:none;
  position:fixed;inset:0;
  background:rgba(0,0,0,0.35);
  z-index:65;
}
.sidebar-overlay.show{display:block}

/* collapsible options */
.more-options{
  border-top:1px solid var(--line);
}
.more-options summary{
  list-style:none;
  cursor:pointer;
  padding:12px 16px;
  font-size:12px;
  font-weight:600;
  color:#6b6a66;
  display:flex;
  align-items:center;
  gap:6px;
  user-select:none;
}
.more-options summary::-webkit-details-marker{display:none}
.more-options .chev{transition:transform .15s ease;font-size:10px}
.more-options[open] .chev{transform:rotate(180deg)}
.sidebar-head h2{
  font-size:11px;
  text-transform:uppercase;
  letter-spacing:0.1em;
  color:#8a8880;
}
.search-box{
  width:100%;
  font-family:var(--mono);
  font-size:12px;
  padding:8px 10px;
  border-radius:6px;
  border:1px solid var(--line);
  background:var(--paper);
  color:var(--ink);
  margin-bottom:10px;
}
.history-list{list-style:none;display:flex;flex-direction:column;gap:6px;max-height:340px;overflow-y:auto}
.history-list li{
  display:flex;align-items:center;gap:6px;
  font-size:12px;
}
.history-list li.empty{color:#9b998f}
.history-list a{
  color:var(--ink);
  text-decoration:none;
  flex:1;
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
  padding:6px 8px;
  border-radius:6px;
  border:1px solid var(--line);
}
.history-list a:hover{border-color:var(--accent)}
.history-del{
  background:none;border:none;color:#9b998f;cursor:pointer;font-size:14px;padding:2px 6px;
}
.history-del:hover{color:var(--accent)}
.sidebar-actions{display:flex;gap:8px;margin-top:12px}

.panel-col{display:flex;flex-direction:column;gap:16px;min-width:0}

.banner{
  display:none;
  background:var(--accent);
  color:#fff;
  padding:10px 14px;
  border-radius:8px;
  font-size:12px;
}
.banner.show{display:block}

.diff-pane{
  display:none;
  border:1px solid var(--line);
  border-radius:12px;
  background:#fff;
  padding:12px;
  font-size:12px;
  max-height:300px;
  overflow-y:auto;
}
html.dark .diff-pane{background:var(--paper-2)}
.diff-pane.show{display:block}
.diff-head{display:flex;align-items:center;gap:10px;margin-bottom:8px;font-weight:600}
.diff-line{white-space:pre-wrap;padding:1px 6px;border-radius:3px;font-family:var(--mono)}
.diff-add{background:rgba(31,180,90,0.15);color:#1a9c4d}
.diff-del{background:rgba(255,90,31,0.15);color:var(--accent);text-decoration:line-through}
.diff-ctx{color:#8a8880}

.panel{
  width:100%;
  background:#fff;
  border:1px solid var(--line);
  border-radius:14px;
  box-shadow:0 1px 0 var(--line), 0 20px 40px -30px rgba(0,0,0,0.25);
  overflow:hidden;
  transition:border-color .15s ease;
}
html.dark .panel{background:var(--paper-2)}
.panel.drag{border-color:var(--accent)}

.panel-bar{
  display:flex;
  align-items:center;
  gap:8px;
  padding:12px 16px;
  border-bottom:1px solid var(--line);
  background:var(--paper-2);
  flex-wrap:wrap;
}
.panel-bar span{
  width:9px;height:9px;border-radius:50%;background:#DDD8CC;
}
.panel-bar select{
  font-family:var(--mono);
  font-size:12px;
  padding:6px 8px;
  border-radius:6px;
  border:1px solid var(--line);
  background:var(--paper);
  color:var(--ink);
}
.btn-sm{padding:6px 10px !important;font-size:12px !important}
.panel-bar .count{
  margin-left:auto;
  font-size:11px;
  color:#8a8880;
}

.editor-wrap{display:flex}
.line-numbers{display:none}
.editor-wrap.show-lines .line-numbers{display:block}
.line-numbers{
  font-family:var(--mono);
  font-size:clamp(14px,1.8vw,16px);
  line-height:1.6;
  color:#B5B2A8;
  padding:clamp(16px,3vw,24px) 0 clamp(16px,3vw,24px) clamp(12px,2vw,16px);
  text-align:right;
  user-select:none;
  overflow:hidden;
  min-height:min(40vh,320px);
  max-height:min(40vh,320px);
  white-space:pre;
  border-right:1px solid var(--line);
}
textarea{
  flex:1;
  width:100%;
  min-height:min(40vh,320px);
  border:none;
  outline:none;
  resize:vertical;
  padding:clamp(16px,3vw,24px);
  font-family:var(--mono);
  font-size:clamp(14px,1.8vw,16px);
  line-height:1.6;
  color:var(--ink);
  background:transparent;
  white-space:pre-wrap;
  word-break:break-word;
}
textarea.nowrap{white-space:pre;overflow-x:auto}
textarea::placeholder{color:#B5B2A8}

.md-preview{
  display:none;
  padding:clamp(16px,3vw,24px);
  border-top:1px solid var(--line);
  font-size:14px;
  line-height:1.6;
}
.md-preview.show{display:block}
.md-preview h1,.md-preview h2,.md-preview h3{font-family:var(--serif);margin:10px 0}
.md-preview code{background:var(--paper-2);padding:2px 5px;border-radius:4px}
.btn-active{background:var(--accent) !important;color:#fff !important;border-color:var(--accent) !important}

.options-row{
  display:flex;
  flex-wrap:wrap;
  gap:14px;
  padding:14px 16px;
  border-top:1px solid var(--line);
}
.opt{
  display:flex;
  flex-direction:column;
  gap:4px;
  font-size:11px;
  color:#8a8880;
  flex:1;
  min-width:140px;
}
.opt select, .opt input[type="password"], .opt input[type="text"]{
  font-family:var(--mono);
  font-size:12px;
  padding:8px 10px;
  border-radius:6px;
  border:1px solid var(--line);
  background:var(--paper);
  color:var(--ink);
}
.opt-checkbox{
  flex-direction:row;
  align-items:center;
  gap:8px;
  flex:0 0 auto;
}
.opt-file input{font-size:11px}

.actions{
  display:flex;
  flex-wrap:wrap;
  gap:10px;
  padding:14px 16px;
  border-top:1px solid var(--line);
  background:var(--paper-2);
}
button, .btn{
  font-family:var(--mono);
  font-size:13px;
  font-weight:600;
  padding:11px 18px;
  border-radius:8px;
  border:1px solid var(--ink);
  background:var(--ink);
  color:var(--paper);
  cursor:pointer;
  transition:transform .12s ease, background .12s ease;
  white-space:nowrap;
}
button:hover{transform:translateY(-1px)}
button:active{transform:translateY(0)}
button:focus-visible, textarea:focus-visible, a:focus-visible, select:focus-visible, input:focus-visible{
  outline:2px solid var(--accent-2);
  outline-offset:2px;
}
.btn-ghost{
  background:transparent;
  color:var(--ink);
  border:1px solid var(--line);
}
.btn-accent{
  background:var(--accent);
  border-color:var(--accent);
  color:#fff;
}
.actions .spacer{flex:1}
#updateBtn{display:none}
#updateBtn.show{display:inline-flex}

.result{
  display:none;
  width:100%;
  padding:16px;
  border:1px solid var(--line);
  border-radius:12px;
  background:#fff;
  align-items:center;
  gap:16px;
  flex-wrap:wrap;
}
html.dark .result{background:var(--paper-2)}
.result.show{display:flex}
.result canvas{border-radius:8px;border:1px solid var(--line);flex-shrink:0}
.result-right{flex:1;min-width:200px;display:flex;flex-direction:column;gap:10px}
.result input{
  width:100%;
  font-family:var(--mono);
  font-size:13px;
  padding:10px 12px;
  border:1px solid var(--line);
  border-radius:8px;
  background:var(--paper);
  color:var(--ink);
}
.result-actions{display:flex;gap:8px;flex-wrap:wrap}
.btn-share{
  display:inline-flex;align-items:center;
  text-decoration:none;
  font-size:12px;
  padding:9px 14px;
}

.toast{
  position:fixed;
  bottom:24px;
  left:50%;
  transform:translateX(-50%) translateY(20px);
  background:var(--ink);
  color:var(--paper);
  padding:10px 18px;
  border-radius:8px;
  font-size:13px;
  opacity:0;
  pointer-events:none;
  transition:opacity .2s ease, transform .2s ease;
  z-index:50;
}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

footer{
  border-top:1px solid var(--line);
  padding:20px clamp(16px,4vw,40px);
  display:flex;
  flex-wrap:wrap;
  gap:8px 20px;
  justify-content:center;
  align-items:center;
  font-size:12px;
  color:#6b6a66;
  text-align:center;
}
footer a{color:var(--ink);text-decoration:none;border-bottom:1px dotted var(--line)}
footer a:hover{border-color:var(--ink)}

.hero-cta{
  display:inline-flex;
  margin-top:16px;
  text-decoration:none;
}

.field-error{
  display:none;
  color:var(--accent);
  font-size:11px;
}
.field-error.show{display:block}
.opt input.invalid{border-color:var(--accent)}

.spinner{
  display:none;
  width:13px;height:13px;
  border:2px solid rgba(255,255,255,0.4);
  border-top-color:#fff;
  border-radius:50%;
  margin-left:8px;
  vertical-align:middle;
  animation:spin .7s linear infinite;
}
button[disabled] .spinner{display:inline-block}
button[disabled]{opacity:0.75;cursor:wait}
@keyframes spin{to{transform:rotate(360deg)}}

.mobile-cta{
  display:none;
  position:fixed;
  bottom:0;left:0;right:0;
  padding:12px 16px calc(12px + env(safe-area-inset-bottom));
  background:var(--paper);
  border-top:1px solid var(--line);
  z-index:40;
}
.mobile-cta button{width:100%}

.cookie-banner{
  display:none;
  position:fixed;
  bottom:0;left:0;right:0;
  background:var(--ink);
  color:var(--paper);
  padding:14px 16px;
  font-size:12px;
  align-items:center;
  justify-content:center;
  gap:14px;
  flex-wrap:wrap;
  z-index:60;
}
.cookie-banner.show{display:flex}
.cookie-banner a{color:var(--paper);text-decoration:underline}

@media (max-width:800px){
  .mobile-cta.show{display:block}
  main{padding-bottom:90px}
}

.seo-copy{
  max-width:640px;
  margin-top:40px;
  padding-top:24px;
  border-top:1px solid var(--line);
  color:#6b6a66;
  font-size:13px;
  line-height:1.7;
}
.seo-copy h2{
  font-family:var(--serif);
  font-size:18px;
  color:var(--ink);
  margin:24px 0 8px;
}
.seo-copy h2:first-child{margin-top:0}
.steps-list, .feature-list{padding-left:20px;margin-bottom:8px}
.steps-list li, .feature-list li{margin-bottom:6px}
.faq details{
  border:1px solid var(--line);
  border-radius:8px;
  padding:10px 14px;
  margin-bottom:8px;
}
.faq summary{cursor:pointer;font-weight:600;color:var(--ink);font-size:13px}
.faq p{margin-top:8px}
.seo-links{margin-top:20px;font-size:12px}
.seo-links a{color:var(--accent)}

@media (max-width:480px){
  .actions{flex-direction:column}
  .actions button, .actions .btn{width:100%}
  .actions .spacer{display:none}
  .result{flex-direction:column}
  .result canvas{align-self:center}
  .line-numbers{display:none}
  .options-row{flex-direction:column}
  .opt{min-width:0}
}