/* ─── RF Link Budget Web — Design System ─────────────────────────────────── */

:root {
  --bg:          #0d1117;
  --bg2:         #161b22;
  --bg3:         #21262d;
  --border:      #30363d;
  --text:        #c9d1d9;
  --text-dim:    #8b949e;
  --text-bright: #f0f6fc;
  --accent:      #1565C0;
  --accent-lt:   #1976D2;
  --green:       #3fb950;
  --yellow:      #d29922;
  --red:         #f85149;
  --blue:        #58a6ff;
  --tab-active:  #1565C0;
  --inp-bg:      #0d1117;
  --inp-border:  #30363d;
  --card-shadow: 0 2px 12px rgba(0,0,0,.5);
}

[data-theme="light"] {
  --bg:          #f6f8fa;
  --bg2:         #ffffff;
  --bg3:         #eaeef2;
  --border:      #d0d7de;
  --text:        #1f2328;
  --text-dim:    #656d76;
  --text-bright: #000000;
  --accent:      #1565C0;
  --accent-lt:   #1976D2;
  --green:       #1a7f37;
  --yellow:      #9a6700;
  --red:         #d1242f;
  --blue:        #0969da;
  --inp-bg:      #ffffff;
  --inp-border:  #d0d7de;
  --card-shadow: 0 1px 4px rgba(0,0,0,.12);
}

*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  font-size: 13px;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

/* ─── Navbar ─────────────────────────────────────────────────────────────── */
.rfb-navbar {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 6px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}
.rfb-navbar .navbar-brand {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-bright);
  letter-spacing: .3px;
}
.rfb-navbar .navbar-brand i { color: var(--accent); }

.rfb-status-badge {
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 20px;
  background: var(--bg3);
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.rfb-status-badge.ok   { background: rgba(63,185,80,.15); color: var(--green); border-color: var(--green); }
.rfb-status-badge.fail { background: rgba(248,81,73,.15); color: var(--red);   border-color: var(--red);   }
.rfb-status-badge.busy { background: rgba(21,101,192,.15);color: var(--blue);  border-color: var(--blue);  }

.rfb-theme-btn {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: 4px 8px;
  border-radius: 6px;
}
.rfb-theme-btn:hover { color: var(--text-bright); }

/* ─── Main layout ────────────────────────────────────────────────────────── */
.rfb-main { padding-top: 10px; padding-bottom: 20px; }

/* ─── Cards ──────────────────────────────────────────────────────────────── */
.rfb-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--card-shadow);
}
.rfb-card-header {
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
  padding: 7px 12px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-bright);
  letter-spacing: .3px;
}

/* ─── Tabs ───────────────────────────────────────────────────────────────── */
.rfb-tabs {
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
  padding: 4px 6px 0;
  gap: 2px;
  flex-wrap: nowrap;
  overflow-x: auto;
  scrollbar-width: thin;
}
.rfb-tabs .nav-link {
  color: var(--text-dim);
  font-size: 12px;
  padding: 5px 10px;
  border: none;
  border-radius: 6px 6px 0 0;
  white-space: nowrap;
  background: transparent;
  transition: color .15s, background .15s;
}
.rfb-tabs .nav-link:hover { color: var(--text-bright); background: var(--bg); }
.rfb-tabs .nav-link.active {
  color: var(--text-bright);
  background: var(--bg2);
  border: 1px solid var(--border);
  border-bottom-color: var(--bg2);
}

.rfb-tab-body { padding: 12px; }

/* ─── Form elements ──────────────────────────────────────────────────────── */
.rfb-label {
  display: block;
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 3px;
  font-weight: 500;
}
.rfb-input, .rfb-select {
  width: 100%;
  background: var(--inp-bg);
  border: 1px solid var(--inp-border);
  border-radius: 5px;
  color: var(--text);
  padding: 4px 8px;
  font-size: 13px;
  outline: none;
  transition: border-color .15s;
  -webkit-appearance: none;
}
.rfb-input:focus, .rfb-select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(21,101,192,.25);
}
.rfb-derived { color: var(--text-dim); font-style: italic; }

.rfb-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24'%3E%3Cpath fill='%238b949e' d='M7 10l5 5 5-5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 6px center;
  padding-right: 24px;
  cursor: pointer;
}
[data-theme="dark"] .rfb-select option { background: #161b22; }

.rfb-hint {
  font-size: 10px;
  color: var(--text-dim);
  margin: 4px 0 0;
}
.rfb-section-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--blue);
  text-transform: uppercase;
  letter-spacing: .6px;
  margin-bottom: 6px;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--border);
}
.rfb-check .form-check-input {
  background-color: var(--bg3);
  border-color: var(--inp-border);
}
.rfb-check .form-check-input:checked {
  background-color: var(--accent);
  border-color: var(--accent);
}
.rfb-file-input {
  font-size: 11px;
  color: var(--text-dim);
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 3px 6px;
  flex: 1;
  min-width: 0;
}
.rfb-file-input::file-selector-button {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text-dim);
  font-size: 11px;
  padding: 1px 6px;
  margin-right: 6px;
  cursor: pointer;
}
.rfb-csv-status {
  font-size: 11px;
  color: var(--text-dim);
  white-space: nowrap;
}
.rfb-csv-status.loaded { color: var(--green); }

/* ─── Buttons ────────────────────────────────────────────────────────────── */
.rfb-btn-primary {
  background: var(--accent);
  border: 1px solid var(--accent-lt);
  color: #fff;
  font-weight: 600;
  font-size: 13px;
  padding: 6px 14px;
  border-radius: 6px;
  transition: background .15s;
}
.rfb-btn-primary:hover { background: var(--accent-lt); color: #fff; }
.rfb-btn-primary:disabled { opacity: .5; }

.rfb-btn-secondary {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 13px;
  padding: 6px 12px;
  border-radius: 6px;
  transition: background .15s, border-color .15s;
}
.rfb-btn-secondary:hover { border-color: var(--accent); color: var(--text-bright); }

/* ─── Results panel ──────────────────────────────────────────────────────── */
.rfb-results-card { display: flex; flex-direction: column; }
.rfb-fm-badge {
  font-size: 13px;
  font-weight: 700;
  padding: 2px 10px;
  border-radius: 12px;
  background: var(--bg3);
  color: var(--text-dim);
  border: 1px solid var(--border);
}
.rfb-fm-badge.ok   { background: rgba(63,185,80,.2);  color: var(--green); border-color: var(--green); }
.rfb-fm-badge.warn { background: rgba(210,153,34,.2); color: var(--yellow);border-color: var(--yellow);}
.rfb-fm-badge.fail { background: rgba(248,81,73,.2);  color: var(--red);   border-color: var(--red);  }

.rfb-results-panel {
  font-family: "Consolas", "Cascadia Code", monospace;
  font-size: 12px;
  padding: 10px;
  min-height: 260px;
  max-height: 420px;
  overflow-y: auto;
  line-height: 1.7;
}
.rfb-results-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 200px;
  color: var(--text-dim);
  text-align: center;
}

/* Result row colors */
.r-hdr  { color: var(--blue);   font-weight: 700; }
.r-ok   { color: var(--green);  }
.r-warn { color: var(--yellow); }
.r-fail { color: var(--red);    }
.r-dim  { color: var(--text-dim); }

/* ─── Graph area ─────────────────────────────────────────────────────────── */
.rfb-plot-area {
  min-height: 380px;
  position: relative;
}
.rfb-plot-placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 380px;
  color: var(--text-dim);
  text-align: center;
}

/* ─── Modal ──────────────────────────────────────────────────────────────── */
.rfb-modal {
  background: var(--bg2);
  border: 1px solid var(--border);
  color: var(--text);
}
.rfb-modal-header {
  background: var(--bg3);
  border-bottom: 1px solid var(--border);
}
.rfb-modal-footer {
  background: var(--bg3);
  border-top: 1px solid var(--border);
}
.rfb-modal .btn-close { filter: invert(1) grayscale(1); }
[data-theme="light"] .rfb-modal .btn-close { filter: none; }

.rfb-info-note {
  font-size: 12px;
  color: var(--blue);
  background: rgba(88,166,255,.1);
  border: 1px solid rgba(88,166,255,.3);
  border-radius: 6px;
  padding: 6px 10px;
  margin-bottom: 10px;
}
.rfb-profile-summary {
  font-size: 12px;
  color: var(--text-dim);
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 5px 10px;
}

/* ─── Spinner ────────────────────────────────────────────────────────────── */
.rfb-spinner-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.65);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
}
.rfb-spinner { color: var(--accent); width: 2.5rem; height: 2.5rem; }
.rfb-spinner-text { color: #fff; font-size: 13px; }

/* ─── Scrollbars ─────────────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-dim); }

/* ─── Responsive overrides ───────────────────────────────────────────────── */
@media (max-width: 575px) {
  .rfb-tabs .nav-link { font-size: 11px; padding: 4px 7px; }
  .rfb-results-panel  { max-height: 300px; }
  .rfb-plot-area      { min-height: 300px; }
  .rfb-plot-placeholder { height: 300px; }
}

/* ─── Sensitivity mode: inactive field greying ───────────────────────────── */
.rfb-field-disabled {
  opacity: 0.38;
  pointer-events: none;
}

/* ─── Cable loss inline section ──────────────────────────────────────────── */
.rfb-cable-label {
  font-size: 10px;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: .5px;
  margin-bottom: 3px;
}
.rfb-cable-info {
  font-size: 10px;
  color: var(--text-dim);
  padding: 2px 0 2px;
  min-height: 16px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.rfb-cable-info.r-ok   { color: var(--green); }
.rfb-cable-info.r-warn { color: var(--yellow); }
.rfb-cable-info.r-fail { color: var(--red); }
.rfb-cable-loss-input {
  background: rgba(21, 101, 192, 0.08) !important;
  border-color: rgba(21, 101, 192, 0.35) !important;
  font-weight: 600;
}
[data-theme="light"] .rfb-cable-loss-input {
  background: rgba(21, 101, 192, 0.06) !important;
}

/* ─── Sensitivity / NF mode notes ────────────────────────────────────────── */
.rfb-mode-note {
  font-size: 10px;
  color: var(--text-dim);
  background: var(--bg3);
  border-left: 2px solid var(--border);
  border-radius: 0 3px 3px 0;
  padding: 3px 8px;
  margin: 3px 0 0;
  min-height: 20px;
}
.rfb-mode-hint {
  display: block;
  font-size: 10px;
  font-style: italic;
  color: var(--text-dim);
  margin-top: 2px;
}
.rfb-mode-hint.active { color: var(--yellow); }

/* ─── Corner logo ────────────────────────────────────────────────────────── */
.rfb-corner-logo {
  position: fixed;
  bottom: 14px;
  right: 14px;
  z-index: 9999;
  opacity: 0.72;
  transition: opacity 0.2s;
  line-height: 0;
  pointer-events: none;   /* never blocks clicks on graphs/controls */
}
.rfb-corner-logo img {
  width: 42px;
  height: 42px;
  object-fit: contain;
  border-radius: 6px;
  display: block;
}
@media (max-width: 575px) {
  .rfb-corner-logo { bottom: 8px; right: 8px; }
  .rfb-corner-logo img { width: 32px; height: 32px; }
}

/* ─── Excel export button ───────────────────────────────────────────────────── */
.rfb-btn-excel {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: #217346;
  font-size: 12px;
  padding: 3px 9px;
  border-radius: 6px;
  font-weight: 500;
  transition: background .15s, border-color .15s;
}
.rfb-btn-excel:hover { border-color: #217346; color: #1a5c38; background: rgba(33,115,70,.1); }
[data-theme="light"] .rfb-btn-excel { color: #1a5c38; }
[data-theme="light"] .rfb-btn-excel:hover { background: rgba(33,115,70,.08); }

/* ─── Help button ────────────────────────────────────────────────────────────── */
.rfb-help-btn {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--blue);
  font-size: 12px;
  padding: 4px 10px;
  border-radius: 6px;
  font-weight: 500;
}
.rfb-help-btn:hover { border-color: var(--blue); color: var(--text-bright); }

/* ─── Field tooltip icons ────────────────────────────────────────────────────── */
.rfb-tip {
  font-size: 9px;
  color: var(--text-dim);
  cursor: help;
  opacity: 0.65;
  margin-left: 3px;
  vertical-align: middle;
}
.rfb-tip:hover { opacity: 1; color: var(--blue); }

/* ─── Results estimate disclaimer ───────────────────────────────────────────── */
.rfb-estimate-note {
  font-size: 10px;
  color: var(--text-dim);
  text-align: center;
  padding: 4px 10px;
  border-top: 1px solid var(--border);
  background: var(--bg3);
  border-radius: 0 0 6px 6px;
}

/* ─── About / Engineering Notes section ─────────────────────────────────────── */
.rfb-about-wrap {
  margin-top: 6px;
  margin-bottom: 10px;
}
.rfb-about-toggle {
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 11px;
  padding: 4px 0;
  cursor: pointer;
  width: 100%;
  text-align: center;
  display: block;
  transition: color .15s;
}
.rfb-about-toggle:hover { color: var(--text); }
.rfb-about-body {
  font-size: 11px;
  color: var(--text-dim);
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 0 0 6px 6px;
  padding: 10px 14px;
  line-height: 1.6;
}
.rfb-about-body strong { color: var(--text); }
.rfb-about-body ul { padding-left: 18px; margin: 4px 0 0; }
.rfb-about-body li { margin-bottom: 2px; }

/* ─── Help modal ─────────────────────────────────────────────────────────────── */
.rfb-help-body {
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--text);
}
.rfb-help-body p  { margin-bottom: 6px; }
.rfb-help-body ol,
.rfb-help-body ul { padding-left: 20px; margin-bottom: 8px; }
.rfb-help-body li { margin-bottom: 3px; }
.rfb-help-section-title {
  font-size: 11px;
  font-weight: 700;
  color: var(--blue);
  text-transform: uppercase;
  letter-spacing: .5px;
  margin-top: 16px;
  margin-bottom: 5px;
  padding-bottom: 3px;
  border-bottom: 1px solid var(--border);
}
.rfb-help-section-title:first-child { margin-top: 0; }
.rfb-shannon-formula {
  font-family: "Consolas", "Cascadia Code", monospace;
  font-size: 12px;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 5px 10px;
  margin: 6px 0;
  display: inline-block;
}
.rfb-disclaimer-box {
  font-size: 11px;
  color: var(--yellow);
  background: rgba(210,153,34,.08);
  border: 1px solid rgba(210,153,34,.3);
  border-radius: 6px;
  padding: 8px 10px;
  margin-top: 14px;
  line-height: 1.5;
}

/* ─── Footer ─────────────────────────────────────────────────────────────── */
.rfb-footer {
  border-top: 1px solid var(--border);
  background: var(--bg2);
  text-align: center;
  padding: 16px 20px 20px;
  margin-top: 16px;
}
.rfb-footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 20px;
  margin-bottom: 8px;
}
.rfb-footer-links a {
  color: var(--text-dim);
  text-decoration: none;
  font-size: 12px;
  transition: color .15s;
}
.rfb-footer-links a:hover { color: var(--blue); }
.rfb-footer-copy { font-size: 11px; color: var(--text-dim); }
.rfb-footer-copy a { color: var(--text-dim); text-decoration: none; }
.rfb-footer-copy a:hover { color: var(--blue); }

/* ─── Static content pages ────────────────────────────────────────────────── */
.rfb-page-wrap {
  max-width: 800px;
  margin: 0 auto;
  padding: 28px 20px 40px;
}
.rfb-page-title {
  font-size: 20px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 4px;
}
.rfb-page-subtitle {
  font-size: 12px;
  color: var(--text-dim);
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}
.rfb-page-section { margin-bottom: 24px; }
.rfb-page-section h2 {
  font-size: 11px;
  font-weight: 700;
  color: var(--blue);
  text-transform: uppercase;
  letter-spacing: .6px;
  margin-bottom: 10px;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border);
}
.rfb-page-section p {
  font-size: 13px;
  line-height: 1.75;
  color: var(--text);
  margin-bottom: 10px;
}
.rfb-page-section ul,
.rfb-page-section ol {
  font-size: 13px;
  line-height: 1.75;
  color: var(--text);
  padding-left: 22px;
  margin-bottom: 10px;
}
.rfb-page-section li { margin-bottom: 4px; }
.rfb-page-section a { color: var(--blue); text-decoration: none; }
.rfb-page-section a:hover { text-decoration: underline; }
.rfb-page-notice {
  font-size: 12px;
  color: var(--yellow);
  background: rgba(210,153,34,.08);
  border: 1px solid rgba(210,153,34,.3);
  border-radius: 6px;
  padding: 10px 14px;
  margin-bottom: 16px;
  line-height: 1.6;
}
.rfb-contact-card {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px 24px;
  margin-bottom: 16px;
}
.rfb-contact-email {
  font-size: 16px;
  font-weight: 600;
  color: var(--blue);
}

/* ─── Mini Calculator Widget (doc pages) ─────────────────────────────────── */
.rfb-mini-calc {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 20px;
}
.rfb-mini-calc-result {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 14px;
  margin-top: 14px;
}
.rfb-result-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 6px 0;
  border-bottom: 1px solid var(--border);
  gap: 12px;
}
.rfb-result-row:last-child { border-bottom: none; }
.rfb-result-label { color: var(--text-dim); font-size: 12px; flex-shrink: 0; }
.rfb-result-value { color: var(--green); font-weight: 700; font-size: 14px; font-family: 'Consolas','Cascadia Code',monospace; white-space: nowrap; }
.rfb-result-value.warn { color: var(--yellow); }
.rfb-result-value.bad  { color: var(--red); }
.rfb-mini-calc-note {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 10px;
  margin-bottom: 0;
  padding: 8px 12px;
  background: var(--bg);
  border-radius: 5px;
  border-left: 3px solid var(--accent);
}
.rfb-mini-calc-error {
  font-size: 12px;
  color: var(--red);
  margin-top: 10px;
  padding: 8px 12px;
  background: rgba(248,81,73,.1);
  border-radius: 5px;
  border-left: 3px solid var(--red);
}
/* KaTeX formula display blocks */
.rfb-formula-block {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 18px 20px;
  margin-bottom: 14px;
  text-align: center;
  overflow-x: auto;
}
.rfb-formula-block .rfb-formula-note {
  font-size: 11px;
  color: var(--text-dim);
  margin-top: 10px;
  margin-bottom: 0;
  text-align: left;
}
.katex { font-size: 1.1em; }
.katex-display { margin: 0.4em 0; }
/* Dark theme: KaTeX color fix */
[data-theme="dark"] .katex { color: var(--text-bright); }
[data-theme="light"] .katex { color: var(--text-bright); }