* {
  box-sizing: border-box;
}

:root {
  --bg: #f8fafc;
  --text: #0f172a;
  --muted: #64748b;
  --primary: #0f5f8f;
  --primary-dark: #0b4568;
  --accent: #38bdf8;
  --card: #ffffff;
  --border: rgba(15, 23, 42, 0.12);
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.12);
}

html,
body {
  margin: 0;
  height: 100%;
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 45%, #ffffff 100%);
  color: var(--text);
}

html {
  scroll-padding-top: 49px;
  scrollbar-gutter: stable;
}

body {
  height: 100vh;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: min(1160px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #e7edf2;
  font-family: Arial, Helvetica, sans-serif;
  flex: 0 0 auto;
}

.nav {
  height: 82px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1.05;
}

.brand img {
  width: 54px;
  height: 54px;
  object-fit: contain;
}

.nav-links {
  display: flex;
  gap: 30px;
  font-size: 0.9rem;
  font-weight: 700;
  color: #203040;
}

.nav-links a:hover {
  color: #087e80;
}

.nav-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: #11a9a8;
  color: white;
  padding: 13px 20px;
  border-radius: 10px;
  font-weight: 800;
  box-shadow: 0 14px 30px rgba(17, 169, 168, 0.24);
}

.nav-button:hover {
  background: #087e80;
}

#app {
  flex: 1 1 auto;
  min-height: 0;
  display: grid;
  grid-template-columns: 360px 1fr;
  overflow: hidden;
}

#panel {
  padding: 22px;
  background: rgba(255, 255, 255, 0.92);
  border-right: 1px solid var(--border);
  box-shadow: var(--shadow);
  overflow-y: auto;
  backdrop-filter: blur(16px);
}

h1 {
  font-size: 24px;
  margin: 0 0 8px;
  line-height: 1.1;
  color: var(--primary-dark);
  letter-spacing: -0.03em;
}

h2 {
  font-size: 12px;
  margin: 24px 0 12px;
  color: var(--primary);
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

p {
  font-size: 14px;
  line-height: 1.5;
}

.muted {
  color: var(--muted);
}

label {
  display: block;
  font-size: 12px;
  color: var(--primary-dark);
  margin: 12px 0 5px;
  font-weight: 700;
}

input[type="range"],
select,
input[type="text"],
input[type="number"] {
  width: 100%;
}

select,
input[type="text"],
input[type="number"] {
  background: #ffffff;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  outline: none;
}

select:focus,
input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.2);
}

.buttons,
.mode-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 12px;
}

.buttons button:nth-child(3) {
  grid-column: span 2;
}

button,
#loadGraphLabel {
  background: var(--primary);
  color: #ffffff;
  border: 1px solid rgba(15, 95, 143, 0.2);
  border-radius: 999px;
  padding: 10px 14px;
  cursor: pointer;
  font-weight: 700;
  font-size: 12px;
  text-align: center;
  box-shadow: 0 8px 18px rgba(15, 95, 143, 0.18);
}

button:hover,
#loadGraphLabel:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
}

button.active,
.mode.active {
  background: #0ea5e9;
  border-color: #0284c7;
}

button.danger,
.danger {
  background: #b91c1c;
}

button.danger:hover,
.danger:hover {
  background: #7f1d1d;
}

.stat {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  border-bottom: 1px solid var(--border);
  padding: 10px 0;
  font-size: 14px;
}

.stat strong {
  text-align: right;
  color: var(--primary-dark);
}

.note {
  background: rgba(14, 165, 233, 0.08);
  border: 1px solid rgba(14, 165, 233, 0.2);
  padding: 12px;
  border-radius: 14px;
}

.selected-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 14px;
  font-size: 13px;
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
}

.selected-card .row {
  display: grid;
  grid-template-columns: 85px 1fr;
  gap: 10px;
  align-items: center;
  margin: 9px 0;
}

.selected-card .actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 12px;
}

#canvasWrap {
  position: relative;
  overflow: hidden;
  background: #e0f2fe;
}

#simCanvas {
  width: 100%;
  height: 100%;
  display: block;
  background: #f8fafc;
  cursor: grab;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}

#simCanvas.editing {
  cursor: crosshair;
}

#hud {
  position: absolute;
  left: 18px;
  bottom: 18px;
  padding: 10px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.88);
  color: var(--primary-dark);
  border: 1px solid var(--border);
  font-size: 13px;
  pointer-events: none;
  max-width: 680px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

@media (max-width: 920px) {
  .nav {
    height: auto;
    padding: 16px 0;
    flex-wrap: wrap;
  }

  .nav-links {
    order: 3;
    width: 100%;
    justify-content: center;
    gap: 18px;
    flex-wrap: wrap;
  }
}

@media (max-width: 760px) {
  #app {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(0, 1fr) auto;
  }

  #panel {
    order: 2;
    border-right: 0;
    border-top: 1px solid var(--border);
    border-bottom: 0;
    max-height: 34dvh;
    padding: 12px 14px;
    box-shadow: 0 -12px 32px rgba(15, 23, 42, 0.12);
  }

  #canvasWrap {
    order: 1;
    min-height: 0;
  }

  h1 {
    font-size: 18px;
    margin-bottom: 4px;
  }

  h2 {
    margin: 14px 0 8px;
  }

  p {
    font-size: 12px;
  }

  #panel > .muted,
  .note {
    display: none;
  }

  .stat {
    padding: 6px 0;
    font-size: 12px;
  }

  label {
    margin: 8px 0 3px;
  }

  .buttons,
  .mode-grid,
  .selected-card .actions {
    gap: 8px;
    margin-top: 8px;
  }

  button,
  #loadGraphLabel {
    min-height: 36px;
    padding: 8px 10px;
  }

  select,
  input[type="text"],
  input[type="number"] {
    padding: 8px 10px;
    border-radius: 10px;
  }

  .selected-card {
    padding: 10px;
    border-radius: 12px;
  }

  #hud {
    left: 10px;
    right: 10px;
    bottom: 10px;
    max-width: none;
    padding: 8px 10px;
    font-size: 12px;
  }
}

@media (max-width: 620px) {
  .nav-button {
    display: none;
  }
}