:root{
  --bg:#000;
  --panel:#000;

  --text:#f3f3f3;
  --muted:#9a9a9a;

  --key:#101010;
  --key2:#141414;
  --op:#1b1b1b;
  --eq:#2b6cff;
  --eqText:#fff;

  --bar:#0a0a0a;
  --sidebar:#070707;
  --line:#1a1a1a;

  --scrollTrack:#0a0a0a;
  --scrollThumb:#2a2a2a;

  --gap:8px;
  --keyH:58px;

  --contentH:388px;
}

*{ box-sizing:border-box; }
html,body{ height:100%; }

/* 1.0.0 - still disable dragging + text highlight globally */
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:Inter, system-ui, -apple-system, Segoe UI, Roboto, Arial;

  user-select:none;
  -webkit-user-select:none;

  -webkit-user-drag:none;
  user-drag:none;
}

/* prevent svg/img dragging */
svg, img{
  -webkit-user-drag:none;
  user-drag:none;
}

/* allow selection ONLY on calculator display */
#screen, #prev{
  user-select:text;
  -webkit-user-select:text;
}

.key{ font-family:"Plus Jakarta Sans", Inter, system-ui, sans-serif; }
.prev, .dlg-body{ font-family:Inter, system-ui, sans-serif; }
.screen{
  font-family:Poppins, Inter, system-ui, sans-serif;
  font-weight:300;
}

/* stop long-press callouts */
button, .key, .icon-btn, .h-item{
  -webkit-touch-callout:none;
}

/* smoother touch response */
button, .key, .icon-btn, .side-btn, .h-item{
  touch-action:manipulation;
}

.hidden{ display:none !important; }

/* ===== INTRO OVERLAY ===== */
.intro{
  position:fixed;
  inset:0;
  background:#000;
  display:grid;
  place-items:center;
  z-index:9999;
  opacity:1;
  transition:opacity .28s ease;
}
.intro.hide{
  opacity:0;
  pointer-events:none;
}
.intro-icon{
  width:86px;
  height:86px;
  opacity:.95;
}

/* ===== TOPBAR ===== */
.topbar{
  position:sticky;
  top:0;
  z-index:20;
  height:38px;
  display:flex;
  align-items:center;
  gap:10px;
  padding:0 10px;
  background:var(--bar);
  border-bottom:1px solid var(--line);
}
.topbar-title{
  font-size:13px;
  letter-spacing:.3px;
  opacity:.9;
}
.topbar-spacer{ flex:1; }

.icon-btn{
  height:28px;
  width:34px;
  display:grid;
  place-items:center;
  background:transparent;
  color:var(--text);
  border:0;
  padding:0;
  cursor:pointer;
  -webkit-tap-highlight-color:transparent;
}
.icon-btn:active{ opacity:.7; }

.menu-icon{ display:grid; gap:4px; }
.menu-icon i{
  display:block;
  width:18px;
  height:2px;
  background:var(--text);
  opacity:.9;
}
.history-icon svg{ color:var(--text); opacity:.95; }

@media (orientation: landscape){
  #historyBtn{ display:none; }
}

/* ===== SIDEBARS ===== */
.sidebar{
  position:fixed;
  top:38px;
  left:0;
  height:calc(100dvh - 38px);
  width:280px;
  background:var(--sidebar);
  z-index:30;
  display:flex;
  flex-direction:column;
  transition:transform .18s ease;
  border-right:1px solid var(--line);
  transform:translateX(-100%);
}
.sidebar.open{ transform:translateX(0); }

.sidebar-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:10px;
  border-bottom:1px solid var(--line);
}
.sidebar-title{ font-size:13px; letter-spacing:.2px; }

.sidebar-body{
  height:100%;
  display:flex;
  flex-direction:column;
  overflow-y:auto;
  overflow-x:hidden;
}

/* sharp dark scrollbar for sidebars */
.sidebar-body::-webkit-scrollbar{ width:10px; }
.sidebar-body::-webkit-scrollbar-track{ background:var(--scrollTrack); }
.sidebar-body::-webkit-scrollbar-thumb{
  background:var(--scrollThumb);
  border-radius:0;
  border:2px solid var(--scrollTrack);
}

.sidebar-section{
  padding:10px;
  border-bottom:1px solid var(--line);
}

/* option rows with descriptions */
.opt-row{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap:12px;
  padding:10px 0;
}
.opt-text{ flex:1; min-width:0; }
.opt-title{
  font-size:13px;
  font-weight:600;
  color:var(--text);
}
.opt-desc{
  margin-top:4px;
  font-size:11.5px;
  line-height:1.25;
  color:var(--muted);
}
.opt-toggle{
  width:42px;
  height:22px;
  margin-top:2px;
}

.side-btn{
  width:100%;
  height:36px;
  background:var(--key2);
  color:var(--text);
  border:1px solid var(--line);
  border-radius:0;
  cursor:pointer;
  font-weight:800;
  font-family:"Plus Jakarta Sans", Inter, system-ui, sans-serif;
  -webkit-tap-highlight-color:transparent;
}
.side-btn:active{ opacity:.75; }
.side-btn-2{ margin-top:10px; }

.sidebar-spacer{
  flex:1;
  min-height:10px;
}

.sidebar-metrics .kv{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px;
  padding:8px 0;
  font-size:12.5px;
}
.kv-val{
  color:var(--muted);
  font-family:Inter, system-ui, sans-serif;
  font-variant-numeric: tabular-nums;
}

.sidebar-foot{
  padding:10px;
  color:var(--muted);
}
.ver-main{
  font-size:12.5px;
  color:var(--text);
  font-weight:600;
}
.ver-sub{
  margin-top:4px;
  font-size:11.5px;
  color:var(--muted);
}

/* History viewport keeps buttons/footer visible */
.history-viewport{
  flex:1;
  min-height:120px;
  overflow:hidden;
  border-bottom:1px solid var(--line);
}
#historySide .history-list{
  height:100%;
  overflow:auto;
  padding:8px 10px;
}
.sidebar-actions{
  border-bottom:1px solid var(--line);
}

/* Backdrop */
.backdrop{
  position:fixed;
  inset:38px 0 0 0;
  background:rgba(0,0,0,.55);
  opacity:0;
  pointer-events:none;
  transition:opacity .18s ease;
  z-index:25;
}
.backdrop.show{
  opacity:1;
  pointer-events:auto;
}

/* ===== APP ===== */
.app{
  min-height:calc(100dvh - 38px);
  display:grid;
  place-items:center;
  padding:14px;
  padding-bottom:calc(14px + env(safe-area-inset-bottom));
}

.calc{
  width:min(92vw, 480px);
  background:var(--panel);
}

.display{
  padding:10px 2px 12px;
  border-bottom:1px solid var(--line);
}

.prev{
  min-height:18px;
  font-size:12px;
  color:var(--muted);
  text-align:right;
  overflow:hidden;
  white-space:nowrap;
  text-overflow:ellipsis;
  padding:0 6px 6px;
}
.prev.placeholder{ visibility:hidden; }

.screen-wrap{ padding:0 6px; }
.screen{
  width:100%;
  text-align:right;
  font-size:44px;
  line-height:1.1;
}

.content-row{
  display:grid;
  grid-template-columns:1fr;
  gap:12px;
  padding-top:10px;
}

.pad{ width:100%; }

.keys{
  display:grid;
  grid-template-columns:repeat(4, 1fr);
  gap:var(--gap);
  /* 1.0.0: allow drag-glide typing without scrolling */
  touch-action:none;
}

.key{
  appearance:none;
  border:1px solid var(--line);
  background:var(--key);
  color:var(--text);
  border-radius:0;
  height:var(--keyH);
  font-size:20px;
  font-weight:800;
  cursor:pointer;
  -webkit-tap-highlight-color:transparent;
  transition:transform .06s ease, filter .12s ease;
}
.key:active{ transform:translateY(1px); filter:brightness(1.08); }

.key-fn{ background:var(--key2); }
.key-op{ background:var(--op); }
.key-eq{ background:var(--eq); color:var(--eqText); border-color:transparent; }
.key-wide{ grid-column:span 4; }

/* ===== HISTORY INLINE (landscape only) ===== */
.history-inline{
  display:none;
  border:1px solid var(--line);
  overflow:hidden;
  height:var(--contentH);
}
.history-inline-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:8px 10px;
  border-bottom:1px solid var(--line);
  font-size:13px;
}
.history-list{
  overflow:auto;
  height:100%;
  padding:8px 10px;
}
.history-list-inline{
  height:calc(var(--contentH) - 42px - 86px);
}
.history-inline-actions{
  padding:10px;
  border-top:1px solid var(--line);
}
.inline-foot{
  margin-top:8px;
  font-size:11.5px;
  color:var(--muted);
}

.btn-row{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:10px;
}
.side-btn-row{ width:100%; }

/* History items */
.h-item{
  padding:8px 0;
  border-bottom:1px solid var(--line);
  cursor:pointer;
  -webkit-tap-highlight-color:transparent;
}
.h-item:last-child{ border-bottom:0; }

.h-exp{
  font-size:12px;
  color:var(--muted);
  text-align:right;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
  font-family:Inter, system-ui, sans-serif;
}
.h-res{
  font-size:16px;
  font-weight:800;
  text-align:right;
  margin-top:4px;
  font-family:"Plus Jakarta Sans", Inter, system-ui, sans-serif;
}
.h-res.placeholder{ visibility:hidden; }

/* Sharp dark scrollbar */
.history-list::-webkit-scrollbar,
.dlg-body-wrap::-webkit-scrollbar{
  width:10px;
}
.history-list::-webkit-scrollbar-track,
.dlg-body-wrap::-webkit-scrollbar-track{
  background:var(--scrollTrack);
}
.history-list::-webkit-scrollbar-thumb,
.dlg-body-wrap::-webkit-scrollbar-thumb{
  background:var(--scrollThumb);
  border-radius:0;
  border:2px solid var(--scrollTrack);
}

/* ===== RIPPLE EFFECT (1.0.0: allow multiple ripples / multi-touch) ===== */
.ripple-target{
  position:relative;
  overflow:hidden;
}
.ripple{
  position:absolute;
  border-radius:999px;
  transform:scale(0);
  opacity:.35;
  background:#fff;
  pointer-events:none;
  animation:ripple .45s ease-out;
}
@keyframes ripple{
  to{ transform:scale(1); opacity:0; }
}

/* ===== ANDROID DARK DIALOG (pop in/out) ===== */
.dialog-root{
  position:fixed;
  inset:0;
  display:grid;
  place-items:center;
  background:rgba(0,0,0,.6);
  z-index:50;
}
.dialog{
  width:min(92vw, 520px);
  background:#1b1b1b;
  color:#f0f0f0;
  border:1px solid #2f2f2f;
  border-radius:0;
  box-shadow:0 18px 50px rgba(0,0,0,.55);

  transform:translateY(12px) scale(.92);
  opacity:0;
  transition:transform .14s ease, opacity .14s ease;
}
.dialog-root.show .dialog{
  transform:translateY(0) scale(1);
  opacity:1;
}
.dialog.closing{
  transform:translateY(12px) scale(.92);
  opacity:0;
}

.dlg-title{
  padding:14px 16px 10px;
  font-size:18px;
  font-weight:600;
  color:#ffffff;
  font-family:Inter, system-ui, sans-serif;
}
.dlg-body-wrap{
  max-height:260px;
  overflow:auto;
  padding:0 16px 12px;
}
.dlg-body{
  font-size:14px;
  line-height:1.35;
  color:#dedede;
}

/* Bottom bar like old Android dark dialogs */
.dlg-actions{
  display:flex;
  background:linear-gradient(#bdbdbd, #a9a9a9);
  border-top:1px solid #2f2f2f;
  justify-content:center;
}
.dlg-actions.two{ justify-content:space-between; }
.dlg-actions.two .dlg-btn{
  flex:1;
  height:46px;
  background:transparent;
  border:0;
  cursor:pointer;
  font-weight:600;
  color:#111;
  font-family:Inter, system-ui, sans-serif;
}
.dlg-actions.two .dlg-btn + .dlg-btn{
  border-left:1px solid rgba(0,0,0,.22);
}
.dlg-actions.one{ padding:10px; }
.dlg-actions.one .dlg-btn{
  width:140px;
  height:40px;
  background:#efefef;
  border:1px solid #9b9b9b;
  color:#111;
  cursor:pointer;
  font-weight:600;
  font-family:Inter, system-ui, sans-serif;
}
.dlg-actions.one .dlg-btn:active{ opacity:.8; }

/* ===== RESPONSIVE ===== */
@media (orientation: portrait){
  :root{ --gap:8px; --keyH:58px; --contentH:388px; }
  .calc{ width:min(86vw, 380px); }
  .screen{ font-size:40px; }
  .history-inline{ display:none !important; }
}
@media (orientation: landscape){
  :root{ --gap:10px; --keyH:60px; --contentH:410px; }
  .calc{ width:min(92vw, 860px); }
  .content-row{
    grid-template-columns:1.15fr .70fr;
    align-items:start;
  }
  .pad{ height:var(--contentH); }
  .keys{
    height:100%;
    grid-auto-rows:var(--keyH);
    align-content:start;
  }
  .history-inline{ display:block; }
}

/* Mobile landscape scaling */
@media (orientation: landscape) and (max-height: 420px){
  :root{ --gap:6px; --keyH:46px; --contentH:306px; }
  .app{
    padding:8px;
    padding-bottom:calc(8px + env(safe-area-inset-bottom));
  }
  .calc{ width:min(98vw, 760px); }
  .screen{ font-size:34px; }
  .prev{ font-size:11px; }
  .content-row{ grid-template-columns:1.20fr .80fr; gap:10px; }
  .key{ font-size:18px; }
  .history-list-inline{ height:calc(var(--contentH) - 40px - 82px); }
  .side-btn{ height:32px; font-size:12.5px; }
  .dlg-title{ font-size:16px; }
  .dlg-body{ font-size:13px; }
}

/* ensure hidden dialog is COMPLETELY gone */
#dialogRoot[hidden]{ display:none !important; }