:root {
  --bg: #121212;
  --fg: #eee;
  --accent: #1e88e5;
  --subaccent: #64b5f6;
  --button-bg: #1a1a1a;
  --button-hover: #333;
  --border: #333;
  --success: #4caf50;
  --error: #ff6b6b;
  --font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}
*, *::before, *::after { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0; height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-family);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}
body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}
header {
  background: #181818;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  border-bottom: 1.5px solid var(--border);
  user-select: none;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  font-weight: 800;
  font-size: 1.6rem;
  color: var(--accent);
  gap: 0.5rem;
}
.logo img {
  height: 64px;
  width: auto;
  display: block;
}
.contact-link {
  color: var(--accent);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  user-select: none;
  padding: 0.25rem 0.5rem;
  border: 1.5px solid var(--accent);
  border-radius: 8px;
  transition: background-color 0.3s ease;
}
.contact-link:hover,
.contact-link:focus {
  background-color: var(--accent);
  color: #121212;
  outline: none;
}
main {
  flex: 1;
  max-width: 960px;
  margin: 1rem auto 2rem;
  padding: 0 1rem;
  display: flex;
  flex-direction: column;
}
.seo-editable {
  background: #1a1a1a;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  font-size: 1rem;
  line-height: 1.4;
  margin-bottom: 2rem;
  outline-offset: 2px;
  outline: none;
  cursor: text;
  min-height: 4.5rem;
  word-break: break-word;
}
#landing-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit,minmax(180px,1fr));
  gap: 1.25rem;
  margin-bottom: 1rem;
}
button.tool-btn {
  background: var(--button-bg);
  border: none;
  color: var(--fg);
  font-size: 1.2rem;
  font-weight: 700;
  padding: 2rem 1rem;
  border-radius: 14px;
  cursor: pointer;
  box-shadow: inset 0 0 6px #0008;
  transition: background-color 0.3s ease;
  user-select: none;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
  line-height: 1.2;
  min-height: 88px;
}
button.tool-btn:hover, button.tool-btn:focus {
  background: var(--button-hover);
  outline: none;
}
section.tool-page {
  display: none;
  flex-direction: column;
}
section.tool-page.active {
  display: flex;
}
h2.tool-title {
  font-weight: 700;
  font-size: 1.9rem;
  margin-bottom: 1rem;
  color: var(--accent);
}
form {
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
label {
  font-weight: 600;
  font-size: 1rem;
  user-select: none;
}
input[type=number], input[type=text], input[type=email], textarea {
  font-size: 1rem;
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  border: 1.5px solid var(--border);
  background: #222;
  color: var(--fg);
  transition: border-color 0.3s ease;
  width: 100%;
  resize: vertical;
  min-height: 2.5rem;
}
input[type=number]:focus, input[type=text]:focus, input[type=email]:focus, textarea:focus {
  border-color: var(--accent);
  outline: none;
}
.optional-label {
  font-style: italic;
  color: #999;
  font-weight: 400;
  margin-left: 0.4rem;
  font-size: 0.85rem;
}
button.primary-btn {
  max-width: 260px;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  border-radius: 14px;
  border: none;
  padding: 1.1rem 0;
  font-size: 1.25rem;
  cursor: pointer;
  user-select: none;
  transition: background-color 0.3s ease;
  align-self: center;
}
button.primary-btn:hover,
button.primary-btn:focus {
  background: #1565c0;
  outline: none;
}
button.back-btn {
  margin-top: 2rem;
  align-self: flex-start;
  background: transparent;
  border: 1.8px solid var(--border);
  border-radius: 10px;
  padding: 0.7rem 1.4rem;
  font-size: 1rem;
  color: var(--fg);
  font-weight: 600;
  cursor: pointer;
  user-select: none;
  transition: border-color 0.3s ease, color 0.3s ease;
}
button.back-btn:hover,
button.back-btn:focus {
  border-color: var(--accent);
  color: var(--accent);
  outline: none;
}
.result-box {
  background: #222;
  border-radius: 12px;
  padding: 1rem 1.25rem;
  margin-top: 1.5rem;
  font-family: "Courier New", Courier, monospace;
  white-space: pre-wrap;
  font-size: 1rem;
  color: var(--fg);
  user-select: text;
  min-height: 6rem;
}
.diagram-container {
  margin-top: 2rem;
  max-width: 800px;
  width: 100%;
  height: 400px;
  border-radius: 14px;
  border: 1.5px solid var(--border);
  background: #1b1b1b;
  user-select: none;
  position: relative;
}
svg#shaft-diagram {
  width: 100%;
  height: 100%;
}
svg#shaft-diagram text {
  font-family: monospace;
  fill: #ccc;
  font-size: 11px;
  user-select: none;
}
.lr-labels {
  display: flex;
  justify-content: space-between;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: #bbb;
  max-width: 800px;
  width: 100%;
  font-family: var(--font-family);
}
.sr-only {
  position: absolute !important;
  width: 1px !important; 
  height: 1px !important; 
  padding: 0 !important; 
  margin: -1px !important; 
  overflow: hidden !important; 
  clip: rect(0,0,0,0) !important; 
  white-space: nowrap !important; 
  border: 0 !important;
}
@media (max-width: 850px) {
  header {
    padding: 1rem 1rem;
  }
  .logo img {
    height: 56px;
  }
  main {
    margin: 1rem 0.75rem 2rem;
    padding: 0 0.75rem;
  }
  .diagram-container {
    height: 320px;
    max-width: 100%;
  }
  .lr-labels {
    max-width: 100%;
  }
  button.primary-btn, button.tool-btn {
    max-width: 100%;
    font-size: 1.1rem;
    padding: 1.6rem 1rem;
    min-height: 70px;
  }
  input[type=number], input[type=text], input[type=email], textarea {
    font-size: 1.1rem;
    min-height: 3rem;
    padding: 0.6rem 0.85rem;
  }
}
@media (max-width: 480px) {
  :root {
    --font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  }
  body {
    font-size: 14px;
  }
  h2.tool-title {
    font-size: 1.5rem;
  }
  input[type=number], input[type=text], input[type=email], textarea {
    font-size: 1rem;
    min-height: 2.8rem;
  }
  .result-box {
    font-size: 0.9rem;
  }
  button.primary-btn {
    font-size: 1.1rem;
    padding: 1rem 0;
  }
  button.tool-btn {
    font-size: 1rem;
    padding: 1.5rem 0.75rem;
    min-height: 64px;
  }
  .logo img {
    height: 48px;
  }
  main {
    margin: 1rem 0.5rem 1.5rem;
    padding: 0 0.5rem;
  }
}