*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
  background: #0d1117;
  color: #e6edf3;
  font-family: 'Segoe UI', system-ui, monospace;
  overflow: hidden;
}

.header {
  background: #161b22;
  border-bottom: 1px solid #30363d;
  padding: 10px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
}
.header h1  { font-size: 16px; color: #58a6ff; font-weight: 700; letter-spacing: .3px; }
.header .sub{ font-size: 12px; color: #8b949e; font-family: monospace; }

.layout {
  display: grid;
  grid-template-columns: 295px 1fr;
  height: calc(100vh - 46px);
}

.sidebar {
  background: #161b22;
  border-right: 1px solid #30363d;
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 11px;
}

.main { display: flex; flex-direction: column; overflow: hidden; }

.tabs {
  display: flex;
  background: #161b22;
  border-bottom: 1px solid #30363d;
  flex-shrink: 0;
}
.tab {
  padding: 8px 16px;
  cursor: pointer;
  font-size: 12px;
  color: #8b949e;
  border-bottom: 2px solid transparent;
  user-select: none;
  transition: color .15s;
  white-space: nowrap;
}
.tab.active        { color: #58a6ff; border-bottom-color: #58a6ff; }
.tab:hover:not(.active) { color: #e6edf3; }

.plot-area {
  flex: 1;
  padding: 10px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.sec-title {
  font-size: 10px;
  text-transform: uppercase;
  color: #8b949e;
  letter-spacing: .8px;
  margin-bottom: 5px;
  padding-bottom: 3px;
  border-bottom: 1px solid #21262d;
}

label {
  display: block;
  font-size: 11px;
  color: #8b949e;
  margin-bottom: 3px;
}
input[type=text] {
  width: 100%;
  background: #0d1117;
  border: 1px solid #30363d;
  border-radius: 5px;
  color: #e6edf3;
  padding: 5px 9px;
  font-size: 12px;
  font-family: monospace;
}
input[type=text]:focus  { outline: none; border-color: #58a6ff; }
input[type=range]       { width: 100%; accent-color: #58a6ff; cursor: pointer; }

.btn {
  width: 100%;
  background: #238636;
  border: none;
  border-radius: 5px;
  color: #fff;
  padding: 7px;
  font-size: 12px;
  cursor: pointer;
  font-weight: 600;
  margin-top: 2px;
}
.btn:hover { background: #2ea043; }

.btn-sm {
  background: #1c2128;
  border: 1px solid #30363d;
  border-radius: 4px;
  color: #8b949e;
  padding: 3px 8px;
  font-size: 10px;
  cursor: pointer;
  margin: 2px;
  font-family: monospace;
}
.btn-sm:hover { border-color: #58a6ff; color: #58a6ff; }

.btn-toggle {
  background: #1c2128;
  border: 1px solid #30363d;
  border-radius: 4px;
  color: #8b949e;
  padding: 4px 10px;
  font-size: 11px;
  cursor: pointer;
  user-select: none;
}
.btn-toggle.on { background: #1a3d2f; border-color: #3fb950; color: #3fb950; }

.chip { display: inline-block; padding: 2px 7px; border-radius: 10px; font-size: 10px; font-family: monospace; margin: 2px; }
.cp   { background: #3d1a1a; color: #f85149; border: 1px solid rgba(248,81,73,.4); }
.cz   { background: #1a3d1a; color: #3fb950; border: 1px solid rgba(63,185,80,.4); }

.info         { background: #0d1117; border: 1px solid #21262d; border-radius: 5px; padding: 8px; font-size: 11px; font-family: monospace; }
.info p       { color: #8b949e; padding: 2px 0; line-height: 1.5; }
.info p span  { color: #e6edf3; }
.info p .g    { color: #3fb950; }
.info p .r    { color: #f85149; }
.info p .b    { color: #58a6ff; }
.info p .y    { color: #d29922; }

.badge    { padding: 4px 10px; border-radius: 4px; font-size: 11px; font-weight: 600; text-align: center; margin-top: 6px; }
.stable   { background: #1a3d1a; color: #3fb950; border: 1px solid rgba(63,185,80,.4); }
.unstable { background: #3d1a1a; color: #f85149; border: 1px solid rgba(248,81,73,.4); }

.err { color: #f85149; font-size: 11px; padding: 4px 0; }

.tf-box { background: #0d1117; border: 1px solid #30363d; border-radius: 6px; padding: 10px; text-align: center; font-family: monospace; font-size: 13px; }
.tf-num { color: #58a6ff; border-bottom: 1px solid #484f58; padding-bottom: 3px; margin-bottom: 3px; word-break: break-all; }
.tf-den { color: #f85149; word-break: break-all; }

.margin-row  { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; margin-top: 4px; }
.margin-card { background: #0d1117; border: 1px solid #21262d; border-radius: 5px; padding: 6px; text-align: center; }
.margin-card .ml { font-size: 10px; color: #8b949e; margin-bottom: 2px; }
.margin-card .mv { font-size: 14px; font-weight: 700; font-family: monospace; }
.mv.ok { color: #3fb950; }
.mv.ng { color: #f85149; }

canvas { display: block; }

.sol-wrap { flex: 1; overflow-y: auto; padding: 4px; }

.sol-card { background: #161b22; border: 1px solid #30363d; border-radius: 6px; margin-bottom: 8px; overflow: hidden; }

.sol-head {
  background: #1c2128;
  padding: 8px 12px;
  font-size: 12px;
  font-weight: 700;
  color: #58a6ff;
  border-bottom: 1px solid #30363d;
  display: flex;
  align-items: center;
  gap: 8px;
}
.sol-num {
  background: #58a6ff;
  color: #0d1117;
  border-radius: 50%;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 700;
  flex-shrink: 0;
}

.sol-body          { padding: 10px 12px; font-size: 11px; font-family: monospace; line-height: 1.8; }
.sol-body .row     { display: flex; justify-content: space-between; padding: 2px 0; border-bottom: 1px solid #21262d; }
.sol-body .row:last-child { border: none; }
.sol-body .lbl     { color: #8b949e; }
.sol-body .val     { color: #e6edf3; }
.sol-body .formula { background: #0d1117; border: 1px solid #21262d; border-radius: 4px; padding: 6px 10px; margin: 4px 0; color: #d2a8ff; font-size: 11px; }
.sol-body .note    { color: #8b949e; font-size: 10px; margin-top: 4px; font-style: italic; }
.sol-body .step    { color: #3fb950; font-weight: 700; }
.sol-body .warn    { color: #d29922; }
.sol-body .b       { color: #58a6ff; }
.sol-body .g       { color: #3fb950; }

.bode-info {
  background: #1c2128;
  border: 1px solid #30363d;
  border-radius: 5px;
  padding: 8px 10px;
  font-size: 11px;
  margin-bottom: 6px;
  display: flex;
  align-items: flex-start;
  gap: 8px;
}
.bode-info .icon { font-size: 16px; flex-shrink: 0; }
.bode-row        { display: flex; align-items: center; gap: 8px; margin-bottom: 4px; }

::-webkit-scrollbar       { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: #0d1117; }
::-webkit-scrollbar-thumb { background: #30363d; border-radius: 3px; }

.menu-btn {
  display: none;
  align-items: center;
  justify-content: center;
  background: #1c2128;
  border: 1px solid #30363d;
  color: #e6edf3;
  font-size: 18px;
  border-radius: 6px;
  width: 34px;
  height: 32px;
  cursor: pointer;
  flex-shrink: 0;
}
.menu-btn:hover { border-color: #58a6ff; color: #58a6ff; }
.backdrop { display: none; }

@media (max-width: 768px) {
  body { overflow: auto; }

  .header {
    padding: 8px 12px;
    height: auto;
    min-height: 46px;
    flex-wrap: wrap;
    gap: 6px;
  }
  .header h1   { font-size: 14px; }
  .header .sub { font-size: 11px; }
  .menu-btn    { display: flex; }

  
  .layout {
    grid-template-columns: 1fr;
    height: auto;
    min-height: calc(100vh - 46px);
    position: relative;
  }

  .sidebar {
    position: fixed;
    top: 0; left: 0; bottom: 0;
    width: 280px;
    max-width: 85vw;
    z-index: 50;
    transform: translateX(-100%);
    transition: transform .25s ease;
    box-shadow: 2px 0 16px rgba(0,0,0,.55);
  }
  .sidebar.open { transform: translateX(0); }

  .backdrop {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.5);
    z-index: 40;
  }

  .main { min-height: calc(100vh - 90px); }

  
  .tabs {
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
  }
  .tab { padding: 9px 13px; font-size: 12px; }

  .plot-area { padding: 6px; min-height: 70vh; }

  
  .sol-body .row { flex-wrap: wrap; gap: 2px; }
  .sol-body .val { word-break: break-word; }
}

@media (max-width: 420px) {
  .header h1 { font-size: 13px; }
  .tf-box    { font-size: 12px; }
  .plot-area { min-height: 75vh; }
}