.modern-subpage {
  --modern-bg: #f8fafc;
  --modern-panel: #ffffff;
  --modern-panel-soft: #f1f5f9;
  --modern-text: #111827;
  --modern-muted: #64748b;
  --modern-line: #e2e8f0;
  --modern-blue: #2563eb;
  --modern-blue-soft: #dbeafe;
  --modern-shadow: 0 18px 45px rgba(15, 23, 42, .08);
  background: var(--modern-bg) !important;
  color: var(--modern-text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans KR", "Apple SD Gothic Neo", sans-serif;
  letter-spacing: 0;
}

.modern-subpage a {
  border-bottom: 0;
}

.modern-subpage #page-wrapper {
  background: var(--modern-bg);
}

.modern-site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid rgba(226, 232, 240, .82);
  background: rgba(248, 250, 252, .92);
  backdrop-filter: blur(16px);
}

.modern-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 68px;
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
}

.modern-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--modern-text);
  font-weight: 800;
  white-space: nowrap;
}

.modern-brand-mark {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: #111827;
  color: #fff;
  font-size: 14px;
  font-weight: 900;
}

.modern-primary-nav,
.modern-category-nav {
  display: flex;
  align-items: center;
  gap: 6px;
}

.modern-primary-nav {
  overflow-x: auto;
}

.modern-primary-nav a {
  padding: 8px 10px;
  border-radius: 7px;
  color: var(--modern-muted);
  font-size: 14px;
  font-weight: 700;
  white-space: nowrap;
}

.modern-primary-nav a:hover {
  background: var(--modern-panel-soft);
  color: var(--modern-text);
}

.modern-category-nav {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 0 0 12px;
  overflow-x: auto;
}

.modern-category-label {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  margin-right: 2px;
  color: var(--modern-muted);
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0;
}

.modern-category-nav a {
  padding: 8px 12px;
  border: 1px solid var(--modern-line);
  border-radius: 999px;
  background: #fff;
  color: #334155;
  font-size: 13px;
  font-weight: 800;
  white-space: nowrap;
}

.modern-category-nav a:hover {
  border-color: #bfdbfe;
  background: #eff6ff;
  color: #1d4ed8;
}

.modern-subpage #header-wrapper {
  padding: 0 !important;
  background: rgba(248, 250, 252, .9) !important;
  border-bottom: 1px solid rgba(226, 232, 240, .82);
  box-shadow: none;
}

.modern-subpage #header {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(1180px, calc(100% - 32px));
}

.modern-subpage #logo {
  position: static;
  width: auto;
  margin: 0;
}

.modern-subpage #logo a {
  display: inline-flex;
  align-items: center;
  width: auto;
  height: auto;
  min-height: 34px;
  padding: 7px 12px;
  border: 0;
  border-radius: 8px;
  background: #111827;
  color: #fff;
  line-height: 1.2;
  letter-spacing: 0;
  text-transform: none;
}

.modern-subpage #nav {
  position: static;
  width: auto;
  height: auto;
  line-height: 1;
}

.modern-subpage #nav > ul > li > a,
.modern-subpage #nav > ul > li > span {
  color: var(--modern-muted);
  border-radius: 7px;
  border: 0;
  padding: 9px 11px;
}

.modern-subpage #nav > ul > li > a:hover,
.modern-subpage #nav > ul > li > span:hover {
  background: var(--modern-panel-soft);
  color: var(--modern-text);
}

.modern-subpage .dropotron {
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  box-shadow: var(--modern-shadow);
}

.modern-subpage .wrapper {
  padding: 34px 0 18px;
  background: var(--modern-bg);
}

.modern-subpage #main {
  width: min(1180px, calc(100% - 32px));
}

.modern-subpage .row {
  align-items: flex-start;
}

.modern-subpage #content {
  overflow: hidden;
  padding: 26px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: var(--modern-panel);
  box-shadow: var(--modern-shadow);
}

.modern-subpage #content header {
  margin-bottom: 18px;
}

.modern-subpage #content h1 {
  margin: 0 0 16px;
  color: var(--modern-text);
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: 0;
}

.modern-subpage #content h3,
.modern-subpage #content h4 {
  color: var(--modern-text);
  font-weight: 700;
  letter-spacing: 0;
}

.modern-subpage #content p,
.modern-subpage #content div,
.modern-subpage #content td,
.modern-subpage #content h4 {
  line-height: 1.65;
}

.modern-subpage #content table[bgcolor],
.modern-subpage #content table[bgcolor="#FFE241"],
.modern-subpage #content table[align="center"] {
  width: 100% !important;
  border: 1px solid var(--modern-line) !important;
  border-radius: 8px;
  background: var(--modern-panel-soft) !important;
  overflow: hidden;
}

.modern-subpage #content textarea,
.modern-subpage #content input[type="text"],
.modern-subpage #content input[type="number"],
.modern-subpage #content input[type="search"],
.modern-subpage #content select {
  max-width: 100%;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: #fff;
  color: var(--modern-text);
  font: inherit;
  padding: 12px 14px;
  outline: none;
}

.modern-subpage #content textarea:focus,
.modern-subpage #content input:focus,
.modern-subpage #content select:focus {
  border-color: var(--modern-blue);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, .14);
}

.modern-subpage button,
.modern-subpage input[type="button"],
.modern-subpage input[type="submit"],
.modern-subpage input[type="reset"],
.modern-subpage .button {
  border: 0;
  border-radius: 8px;
  background: var(--modern-blue);
  color: #fff;
  font: inherit;
  font-weight: 800;
  padding: 11px 16px;
  cursor: pointer;
}

.modern-subpage button:hover,
.modern-subpage input[type="button"]:hover,
.modern-subpage input[type="submit"]:hover,
.modern-subpage input[type="reset"]:hover,
.modern-subpage .button:hover {
  background: #1d4ed8;
  color: #fff;
}

.modern-subpage #sidebar > section,
.modern-subpage #sidebar section {
  margin-top: 0;
  padding: 18px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: var(--modern-panel);
  box-shadow: 0 12px 28px rgba(15, 23, 42, .05);
}

.modern-sidebar {
  display: grid;
  gap: 14px;
}

.modern-sidebar-card {
  padding: 18px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: var(--modern-panel);
  box-shadow: 0 12px 28px rgba(15, 23, 42, .05);
}

.modern-sidebar-card h3 {
  margin: 0 0 12px;
  color: var(--modern-text);
  font-size: 17px;
  font-weight: 800;
  line-height: 1.3;
}

.modern-sidebar-links {
  display: grid;
  gap: 8px;
}

.modern-sidebar-links a {
  display: block;
  padding: 11px 12px;
  border-radius: 7px;
  background: var(--modern-panel-soft);
  color: #334155;
}

.modern-sidebar-links a:hover {
  background: var(--modern-blue-soft);
  color: #1d4ed8;
}

.modern-sidebar-links strong {
  display: block;
  margin-bottom: 3px;
  font-size: 14px;
  line-height: 1.35;
}

.modern-sidebar-links span {
  display: block;
  color: var(--modern-muted);
  font-size: 12px;
  line-height: 1.4;
}

.modern-sidebar-links.compact a {
  padding: 9px 10px;
}

.modern-sidebar-links.compact strong {
  margin-bottom: 0;
}

.modern-sidebar-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.modern-sidebar-chips a {
  padding: 7px 10px;
  border: 1px solid var(--modern-line);
  border-radius: 999px;
  background: #fff;
  color: #334155;
  font-size: 13px;
  font-weight: 700;
}

.modern-sidebar-chips a:hover {
  border-color: var(--modern-blue);
  color: var(--modern-blue);
}

.modern-category-list {
  display: grid;
  gap: 8px;
}

.modern-category-list details {
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: #fff;
  overflow: hidden;
  scroll-margin-top: 126px;
}

.modern-category-list details[open] {
  border-color: #bfdbfe;
  box-shadow: 0 10px 22px rgba(37, 99, 235, .08);
}

.modern-category-list summary {
  cursor: pointer;
  list-style: none;
  padding: 11px 12px;
  color: var(--modern-text);
  font-size: 14px;
  font-weight: 800;
}

.modern-category-list summary::-webkit-details-marker {
  display: none;
}

.modern-category-list summary::after {
  content: "+";
  float: right;
  color: var(--modern-muted);
  font-weight: 900;
}

.modern-category-list details[open] summary::after {
  content: "-";
}

.modern-category-list details > div {
  display: grid;
  gap: 2px;
  padding: 0 8px 10px;
}

.modern-category-list details a {
  display: block;
  padding: 8px 9px;
  border-radius: 7px;
  color: #334155;
  font-size: 13px;
  line-height: 1.35;
}

.modern-category-list details a:hover {
  background: var(--modern-panel-soft);
  color: var(--modern-blue);
}

.modern-sidebar-note p {
  margin: 0;
  color: var(--modern-muted);
  font-size: 14px;
  line-height: 1.6;
}

.modern-subpage #sidebar h3 {
  margin-bottom: 12px;
  color: var(--modern-text);
  font-size: 18px;
  font-weight: 800;
}

.modern-subpage #sidebar ul {
  max-height: 760px;
  overflow: auto;
  padding-left: 0;
  list-style: none;
}

.modern-subpage #sidebar li {
  padding-left: 0;
}

.modern-subpage #sidebar a {
  display: block;
  padding: 9px 10px;
  border-radius: 7px;
  color: #334155;
  font-size: 14px;
}

.modern-subpage #sidebar a:hover {
  background: var(--modern-panel-soft);
  color: var(--modern-blue);
}

.modern-subpage #copyright {
  width: min(1180px, calc(100% - 32px));
  margin: 22px auto 0;
  padding: 20px 0 34px;
  border-top: 1px solid var(--modern-line);
  color: var(--modern-muted);
  text-align: left;
}

.modern-subpage #copyright .menu {
  text-align: left;
}

.modern-subpage .password-display {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 10px;
  margin: 18px 0;
}

.modern-subpage .options {
  display: grid;
  gap: 12px;
  margin: 18px 0;
  text-align: left;
}

.modern-tool-hero {
  display: grid;
  gap: 9px;
  margin-bottom: 20px;
}

.modern-tool-hero span {
  color: var(--modern-blue);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}

.modern-tool-hero p {
  max-width: 720px;
  margin: 0;
  color: var(--modern-muted);
  font-size: 16px;
}

.modern-tool-panel {
  display: grid;
  gap: 16px;
  margin-top: 16px;
  padding: 20px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: #fff;
}

.modern-tool-panel h2 {
  margin: 0;
  color: var(--modern-text);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0;
}

.modern-field-row {
  display: grid;
  gap: 8px;
}

.modern-field-row label,
.modern-form-grid label,
.modern-range-panel label {
  color: var(--modern-text);
  font-weight: 800;
}

.modern-inline-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.modern-inline-controls input {
  flex: 1 1 260px;
}

.modern-help {
  margin: 0;
  color: var(--modern-muted);
  font-size: 14px;
}

.modern-check-grid {
  display: grid;
  gap: 10px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.modern-check-grid label,
.modern-radio-group label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: #334155;
  font-weight: 700;
}

.modern-result-list {
  display: grid;
  gap: 8px;
  margin: 0;
}

.modern-result-list div {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 10px;
  padding: 10px 12px;
  border-radius: 8px;
  background: var(--modern-panel-soft);
}

.modern-result-list dt {
  color: var(--modern-muted);
  font-weight: 800;
}

.modern-result-list dd {
  margin: 0;
  color: var(--modern-text);
}

.modern-steps {
  margin: 0;
  padding-left: 22px;
  color: #334155;
}

.modern-radio-group {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 0 0 16px;
  padding: 0;
  border: 0;
}

.modern-radio-group legend {
  width: 100%;
  margin-bottom: 4px;
  color: var(--modern-text);
  font-weight: 800;
}

.modern-form-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.modern-form-grid label {
  display: grid;
  gap: 7px;
}

.modern-wide-field {
  grid-column: 1 / -1;
}

.modern-split-input {
  display: grid;
  gap: 8px;
  grid-template-columns: minmax(0, 1fr) minmax(120px, .55fr);
}

.svg-viewer-stage {
  position: relative;
  min-height: 520px;
  overflow: hidden;
  border: 1px dashed #94a3b8;
  border-radius: 8px;
  background: #f8fafc;
}

.svg-viewer-stage #control,
.svg-viewer-stage #info,
.svg-viewer-stage #dropArea {
  position: absolute;
}

.svg-viewer-stage #control {
  z-index: 3;
  padding: 10px 12px;
  border-radius: 8px;
  background: rgba(17, 24, 39, .88);
  color: #fff;
  font-size: 14px;
  font-weight: 800;
}

.svg-viewer-stage #info {
  z-index: 2;
  padding: 8px 10px;
  border-radius: 8px;
  background: rgba(255, 255, 255, .92);
  color: var(--modern-text);
  font-size: 14px;
  font-weight: 800;
}

.svg-viewer-stage #dropArea {
  display: grid;
  place-items: center;
  color: #94a3b8;
  font-size: clamp(24px, 5vw, 48px);
  font-weight: 900;
}

.svg-viewer-stage #dropArea.hover {
  background: #eff6ff;
  color: var(--modern-blue);
}

.svg-viewer-stage #dropArea svg {
  width: 100%;
  height: 100%;
}

.modern-file-picker {
  display: grid;
  gap: 10px;
  padding: 18px;
  border: 1px dashed #94a3b8;
  border-radius: 8px;
  background: var(--modern-panel-soft);
}

.modern-file-picker span {
  color: var(--modern-text);
  font-size: 18px;
  font-weight: 800;
}

#selected_pdf_list {
  min-height: 46px;
  padding: 12px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: var(--modern-panel-soft);
}

#selected_pdf_list li {
  padding: 8px 10px;
  border-radius: 7px;
  background: #fff;
}

.modern-range-panel {
  display: grid;
  gap: 12px;
}

.subnet-calculator {
  background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

.subnet-form {
  display: grid;
  gap: 18px;
}

.subnet-input-card {
  display: grid;
  gap: 18px;
  padding: 20px;
  border: 1px solid #bfdbfe;
  border-radius: 8px;
  background: #eff6ff;
}

.subnet-input-card h2 {
  margin: 0 0 6px;
}

.subnet-input-card p {
  margin: 0;
  color: var(--modern-muted);
}

.subnet-class-group {
  margin: 0;
  padding: 12px;
  border: 1px solid #dbeafe;
  border-radius: 8px;
  background: rgba(255, 255, 255, .72);
}

.subnet-input-grid {
  display: grid;
  gap: 14px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.subnet-input-grid label,
.subnet-result-card {
  display: grid;
  gap: 8px;
  min-width: 0;
  color: var(--modern-text);
  font-weight: 800;
}

.subnet-input-grid input,
.subnet-result-card input,
.subnet-result-card select {
  width: 100%;
  min-width: 0;
}

.subnet-results-grid {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.subnet-result-card {
  padding: 15px;
  border: 1px solid var(--modern-line);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 10px 22px rgba(15, 23, 42, .045);
}

.subnet-result-card input[readonly],
.subnet-result-card input[disabled] {
  background: #f8fafc;
  color: #0f172a;
  font-weight: 800;
}

.subnet-wide-card {
  grid-column: 1 / -1;
}

@media screen and (max-width: 760px) {
  .modern-subpage #header {
    min-height: auto;
    align-items: flex-start;
    flex-direction: column;
    padding: 14px 0;
  }

  .modern-subpage #nav {
    width: 100%;
    overflow-x: auto;
  }

  .modern-subpage #nav > ul {
    white-space: nowrap;
  }

  .modern-nav {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
    min-height: auto;
    padding: 14px 0 10px;
  }

  .modern-primary-nav {
    width: 100%;
    padding-bottom: 2px;
  }

  .modern-category-nav {
    width: min(100% - 24px, 1180px);
    padding-bottom: 10px;
  }

  .modern-subpage .wrapper {
    padding: 20px 0 12px;
  }

  .modern-subpage #main {
    width: min(100% - 24px, 1180px);
  }

  .modern-subpage #content {
    padding: 20px;
  }

  .modern-subpage #content input[type="text"],
  .modern-subpage #content textarea {
    width: 100% !important;
  }

  .modern-subpage .password-display {
    grid-template-columns: 1fr;
  }

  .modern-form-grid,
  .modern-split-input,
  .subnet-input-grid,
  .subnet-results-grid {
    grid-template-columns: 1fr;
  }

  .modern-result-list div {
    grid-template-columns: 1fr;
  }

  .svg-viewer-stage {
    min-height: 420px;
  }
}