/* ============================================================
   FatahCalc Pro — Precision Dark: reset, typography, shell
   ============================================================ */

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

/* Load-bearing: the only guarantee that [hidden] beats component display rules. */
[hidden] { display: none !important; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: var(--font-body);
  font-size: var(--fs-base);
  line-height: 1.6;
  color: var(--text);
  background-color: var(--bg);
  background-image: var(--bg-tint), var(--noise);
  background-size: auto, 24px 24px;
  background-repeat: no-repeat, repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  transition: background-color var(--t-mid), color var(--t-mid);
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  line-height: 1.15;
  margin: 0 0 var(--sp-3);
  letter-spacing: -0.025em;
  color: var(--text);
}
h1 { font-size: var(--fs-2xl); font-weight: 800; }
h2 { font-size: var(--fs-xl); font-weight: 700; }
h3 { font-size: var(--fs-lg); font-weight: 600; }
p { margin: 0 0 var(--sp-3); }

a { color: var(--primary); text-decoration: none; transition: color var(--t-fast); }
a:hover { color: var(--primary-strong); }

ul, ol { margin: 0 0 var(--sp-3); padding-left: 1.15rem; }
li { margin-bottom: .3rem; }

code, kbd, samp, .mono { font-family: var(--font-mono); font-size: .92em; }

:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  border-radius: var(--r-xs);
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 200;
  background: var(--button-bg);
  color: var(--button-text);
  padding: .6rem 1rem;
  border-radius: 0 0 var(--r-sm) 0;
  font-weight: 600;
}
.skip-link:focus { left: 0; }

/* ---------------- Header ---------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--glass);
  backdrop-filter: saturate(150%) blur(20px);
  -webkit-backdrop-filter: saturate(150%) blur(20px);
  border-bottom: 1px solid var(--border-soft);
}

.header-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  min-height: var(--header-h);
  padding: .6rem 1rem;
  display: flex;
  align-items: center;
  gap: 1.1rem;
}
@media (min-width: 768px) { .header-inner { padding-inline: 1.5rem; } }
@media (min-width: 1024px) { .header-inner { padding-inline: 2rem; } }

.brand {
  display: inline-flex;
  align-items: center;
  gap: .65rem;
  color: var(--text);
  flex-shrink: 0;
}
.brand:hover { color: var(--text); }

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  flex-shrink: 0;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: #0f172a;
  box-shadow: 0 6px 18px -12px rgba(0, 0, 0, .8), inset 0 1px 0 rgba(255, 255, 255, .08);
  transition: transform var(--t-mid), border-color var(--t-mid);
}
.brand:hover .brand-mark { transform: translateY(-1px); border-color: var(--border); }
.brand-logo { display: block; width: 34px; height: 34px; object-fit: contain; }

.brand-wordmark { display: flex; flex-direction: column; gap: .18rem; }
.brand-text {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.08rem;
  line-height: 1.1;
  letter-spacing: -.03em;
  white-space: nowrap;
}
.brand-pro {
  font-family: var(--font-mono);
  font-size: .58em;
  font-weight: 600;
  letter-spacing: .04em;
  padding: .14rem .32rem;
  margin-left: .1rem;
  border-radius: 5px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--primary);
  vertical-align: middle;
}
.brand-byline {
  font-family: var(--font-mono);
  font-size: 8.5px;
  font-weight: 500;
  letter-spacing: .18em;
  color: var(--text-faint);
}

/* Wrapper: desktop row, mobile drawer */
.header-panel {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex: 1 1 auto;
  min-width: 0;
}

@media (min-width: 1101px) {
  .header-panel .main-nav { flex: 1 1 auto; justify-content: center; margin-left: 0; }
}

.main-nav { display: flex; gap: .15rem; margin-left: var(--sp-2); }
.nav-icon { display: none; }
.main-nav a {
  padding: .45rem .7rem;
  border-radius: 10px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: .82rem;
  transition: color var(--t-fast), background var(--t-fast);
  white-space: nowrap;
}
.main-nav a:hover { color: var(--text); background: var(--surface-2); }
.main-nav a.is-active {
  color: var(--primary);
  background: var(--primary-soft);
  box-shadow: inset 0 0 0 1px var(--border-soft);
}

.header-actions { margin-left: auto; display: flex; align-items: center; gap: .45rem; }

.instrument-chip {
  display: none;
  align-items: center;
  gap: .45rem;
  padding: .38rem .65rem;
  border-radius: var(--r-pill);
  border: 1px solid var(--border-soft);
  background: var(--surface-2);
  color: var(--text-muted);
  font: 500 10.5px/1 var(--font-mono);
  letter-spacing: .01em;
  white-space: nowrap;
}
@media (min-width: 1260px) { .instrument-chip { display: inline-flex; } }

.status-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 0 3px rgba(52, 211, 153, .12);
  flex-shrink: 0;
}
.status-dot--accent { background: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }
.status-dot--violet { background: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

/* ---------------- Search ---------------- */
.search-wrap { position: relative; display: flex; align-items: center; }
.search-icon {
  position: absolute;
  left: .85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-faint);
  font-size: .82rem;
  pointer-events: none;
  transition: color var(--t-fast);
}
.search-wrap:focus-within .search-icon { color: var(--primary); }

.search-wrap .search-input {
  width: 210px;
  height: 38px;
  padding: .4rem 3.1rem .4rem 2.35rem;
  border-radius: 10px;
  border: 1px solid var(--border-soft);
  background: var(--surface-2);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 11.5px;
  text-overflow: ellipsis;
  transition: width var(--t-mid), border-color var(--t-fast), box-shadow var(--t-fast), background var(--t-fast);
}
.search-wrap .search-input::placeholder { color: var(--text-faint); opacity: 1; }
.search-wrap .search-input:hover { border-color: var(--border); background: var(--surface-3); }
.search-wrap .search-input:focus {
  outline: none;
  width: 250px;
  background: var(--surface);
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--ring);
}
.search-wrap .search-input:focus::placeholder { color: var(--text-faint); }

.search-kbd {
  position: absolute;
  right: .4rem;
  padding: .12rem .3rem;
  border: 1px solid var(--border-soft);
  border-radius: 4px;
  color: var(--text-faint);
  background: var(--surface);
  font-family: var(--font-mono);
  font-size: 8.5px;
  pointer-events: none;
  white-space: nowrap;
}
.search-input:focus ~ .search-kbd { opacity: 0; }

.search-dropdown {
  position: absolute;
  top: calc(100% + .55rem);
  right: 0;
  width: min(380px, 86vw);
  max-height: 60vh;
  overflow-y: auto;
  background: var(--glass-strong);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  box-shadow: var(--shadow-lg);
  padding: .35rem;
  z-index: 120;
  animation: pop-in var(--t-fast) both;
}
.search-result {
  display: flex;
  align-items: center;
  gap: .6rem;
  width: 100%;
  padding: .5rem .55rem;
  border-radius: var(--r-sm);
  color: var(--text);
  font-size: var(--fs-sm);
}
.search-result:hover, .search-result.is-active {
  background: var(--surface-2);
  color: var(--text);
}
.search-result i { color: var(--primary); width: 1rem; text-align: center; font-size: .8rem; }
.search-result small {
  color: var(--text-faint);
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: .02em;
}
.search-empty {
  padding: .8rem;
  color: var(--text-muted);
  font-size: var(--fs-sm);
  text-align: center;
}

.header-inner .nav-toggle { display: none; }
.action-label { display: none; }
#fatahtech-link:hover { color: var(--primary); }

.route-progress {
  height: 2px;
  width: 0;
  background: var(--gradient-brand);
  transition: width var(--t-mid), opacity var(--t-mid);
  opacity: 0;
}
.route-progress.is-loading { width: 70%; opacity: 1; }
.route-progress.is-done { width: 100%; opacity: 0; }

/* ---------------- Main ---------------- */
#main-content {
  flex: 1 0 auto;
  max-width: var(--wrap);
  width: 100%;
  margin: 0 auto;
  padding: 1.5rem 1rem 3.5rem;
  outline: none;
}
@media (min-width: 768px) { #main-content { padding: 2rem 1.5rem 4rem; } }
@media (min-width: 1024px) { #main-content { padding: 2rem 2rem 4.5rem; } }
.route-view { animation: route-in var(--t-slow) both; }

@keyframes route-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}
@keyframes pop-in {
  from { opacity: 0; transform: translateY(-4px) scale(.99); }
  to { opacity: 1; transform: none; }
}

/* ---------------- Footer ---------------- */
.site-footer {
  border-top: 1px solid var(--border-soft);
  background: var(--surface);
  margin-top: auto;
}
.footer-inner {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 2.5rem 1rem 2rem;
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 1.5rem;
}
@media (min-width: 768px) { .footer-inner { padding-inline: 1.5rem; } }
@media (min-width: 1024px) { .footer-inner { padding-inline: 2rem; } }
.footer-brand .brand { margin-bottom: .6rem; }
.footer-brand .brand-mark { width: 36px; height: 36px; border-radius: 10px; }
.footer-brand .brand-logo { width: 29px; height: 29px; }
.footer-brand strong {
  font-family: var(--font-display);
  font-size: 1.02rem;
  font-weight: 700;
  letter-spacing: -.02em;
}
.footer-brand p { color: var(--text-muted); font-size: var(--fs-sm); margin: .2rem 0 0; max-width: 42ch; }
.footer-brand p a, .footer-note a { text-decoration: underline; text-underline-offset: 2px; }
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: .45rem 1.2rem;
  align-content: start;
  justify-content: flex-end;
}
.footer-links a {
  font-size: 12.5px;
  color: var(--text-muted);
}
.footer-links a:hover { color: var(--primary); }
.footer-status {
  grid-column: 1 / -1;
  display: flex;
  flex-wrap: wrap;
  gap: .55rem 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border-soft);
  font: 500 10.5px/1.4 var(--font-mono);
  color: var(--text-faint);
  letter-spacing: .02em;
}
.footer-status span { display: inline-flex; align-items: center; gap: .45rem; }
.footer-note {
  grid-column: 1 / -1;
  margin: 0;
  padding-top: .9rem;
  border-top: 1px dashed var(--border-soft);
  color: var(--text-faint);
  font-size: 11px;
  font-family: var(--font-mono);
}
.footer-note a { color: var(--text-muted); }
.footer-note a:hover { color: var(--primary); }

/* ---------------- Responsive ---------------- */
@media (max-width: 1300px) and (min-width: 1101px) {
  .header-inner { gap: .8rem; }
  .main-nav a { padding: .42rem .55rem; font-size: .78rem; }
  .header-actions { gap: .35rem; }
}

/* ---- Mobile drawer ---- */
@media (max-width: 1100px) {
  .header-inner .nav-toggle { display: inline-flex; margin-left: auto; order: 3; }

  .header-panel {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: .4rem;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: .8rem 1.25rem 1.25rem;
    box-shadow: var(--shadow-md);
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    transition: opacity var(--t-fast), transform var(--t-fast);
  }
  .header-panel.is-open { opacity: 1; transform: none; pointer-events: auto; }

  .main-nav { flex-direction: column; gap: .15rem; margin-left: 0; }
  .main-nav a {
    display: flex;
    align-items: center;
    gap: .7rem;
    padding: .68rem .8rem;
    border-radius: var(--r-sm);
    font-size: var(--fs-md);
  }
  .nav-icon { display: inline-block; width: 1.1rem; text-align: center; color: var(--text-faint); }
  .main-nav a.is-active .nav-icon { color: var(--primary); }

  .header-actions {
    margin-left: 0;
    flex-direction: column;
    align-items: stretch;
    gap: .15rem;
    padding-top: .5rem;
    border-top: 1px dashed var(--border-soft);
  }
  .instrument-chip {
    display: inline-flex;
    align-self: flex-start;
    margin-bottom: .3rem;
    font-size: 10px;
  }
  .search-wrap {
    order: -1;
    width: 100%;
    margin-bottom: .55rem;
    padding-bottom: .65rem;
    border-bottom: 1px dashed var(--border-soft);
  }
  .search-wrap .search-input,
  .search-wrap .search-input:focus { width: 100%; height: 42px; font-size: 12.5px; }
  .search-kbd { display: none; }
  .search-dropdown { width: 100%; left: 0; right: 0; }

  .header-actions .action-btn {
    display: flex;
    width: 100%;
    justify-content: flex-start;
    align-items: center;
    gap: .7rem;
    height: auto;
    padding: .68rem .8rem;
    border: 0;
    background: transparent;
    border-radius: var(--r-sm);
    color: var(--text-muted);
    font-size: var(--fs-md);
    font-weight: 500;
  }
  .header-actions .action-btn:hover { background: var(--surface-2); color: var(--text); }
  .header-actions .action-btn i { width: 1.1rem; text-align: center; flex-shrink: 0; }
  .action-label { display: inline; }

  .footer-inner { grid-template-columns: 1fr; }
  .footer-links { justify-content: flex-start; }
}

@media (max-width: 420px) {
  .brand-text { font-size: .99rem; }
  .brand-mark { width: 38px; height: 38px; }
  .brand-logo { width: 30px; height: 30px; }
  .brand-byline { font-size: 7.5px; letter-spacing: .14em; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    transition-duration: .001ms !important;
  }
}