/* =========================================================
   FULL DARK THEME — REM SCALE — STICKY HEADER VISIBLE —
   MOBILE SIDEBAR FILLS REMAINING SCREEN (UNDER HEADER)
   Fonts: TTF variable only (as requested)
   ========================================================= */

/* =========================
   Source Sans 3 Variable (self-hosted, TTF only)
   ========================= */
@font-face {
  font-family: "Source Sans 3";
  src: url("/static/fonts/SourceSans3-VariableFont_wght.ttf") format("truetype-variations");
  font-weight: 200 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Source Sans 3";
  src: url("/static/fonts/SourceSans3-Italic-VariableFont_wght.ttf") format("truetype-variations");
  font-weight: 200 900;
  font-style: italic;
  font-display: swap;
}

/* =========================
   Root + Palette + Scale
   ========================= */
:root {
  font-size: 100%;
  /* 1rem = 16px baseline */

  --nasa-blue: #0b3d91;
  --nasa-blue-light: #105bd8;
  --nasa-blue-dark: #061f4a;
  --nasa-red: #dd361c;
  --nasa-red-dark: #c62d1f;
  --nasa-red-darker: #99231b;
  --nasa-red-light: #e59892;
  --nasa-red-lightest: #f9e0de;
  --nasa-gray-darkest: #212121;
  --nasa-gray-dark: #323a45;
  --nasa-gray: #5b616b;
  --nasa-gray-light: #aeb0b5;
  --nasa-gray-lighter: #d6d7d9;
  --nasa-gray-lightest: #f1f1f1;
  --nasa-accent-cyan: #02bfe7;
  --nasa-accent-blue: #205493;
  --nasa-accent-green: #2e8540;
  --nasa-accent-gold: #ff9d1e;

  /* Dark theme tokens */
  --bg: #212121;
  --fg: #f1f1f1;
  --muted: #aeb0b5;
  --bar: #212121;
  --barfg: #f1f1f1;
  --side: #212121;
  --border: #3a3a3a;
  --hover: rgba(255, 255, 255, .08);
  --elev-1: #232323;
  --elev-2: #2a2a2a;
  --code-bg: #0b0d17;
  --code-stroke: #1f2937;

  --accent: #105bd8;
  --accent-warm: #dd361c;

  --sidebar-w: 21.25rem;
  /* 340px */

  /* Typographic scale (1.25 modular) */
  --font--2: 0.64rem;
  --font--1: 0.80rem;
  --font-0: 1.00rem;
  --font-1: 1.25rem;
  --font-2: 1.5625rem;
  --font-3: 1.953rem;
  --font-4: 2.441rem;
  --font-5: 3.052rem;

  --lh-body: 1.5;
  --lh-heading: 1.2;

  /* Spacing scale */
  --space-1: var(--font--1);
  --space-2: var(--font-0);
  --space-3: var(--font-1);
  --space-4: var(--font-2);
}

/* =========================
   Base + Typography
   ========================= */
* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: "Source Sans 3", system-ui, -apple-system, "Segoe UI",
    Roboto, Ubuntu, Cantarell, "Noto Sans", Arial, sans-serif;
  font-weight: 400;
  font-size: var(--font-0);
  line-height: var(--lh-body);
  background: var(--bg);
  color: var(--fg);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: Helvetica, "Helvetica Neue", Arial, system-ui, sans-serif;
  font-weight: 700;
  line-height: var(--lh-heading);
  color: #fff;
  margin-top: 1.4em;
  margin-bottom: 0.6em;
}

h1 {
  font-size: var(--font-4);
}

h2 {
  font-size: var(--font-3);
}

h3 {
  font-size: var(--font-2);
}

h4 {
  font-size: var(--font-1);
}

h5 {
  font-size: var(--font-0);
}

h6 {
  font-size: var(--font--1);
  text-transform: uppercase;
  font-weight: 400;
  color: var(--muted);
  line-height: 1.3;
}

.lead {
  font-size: var(--font-1);
  font-weight: 300;
  color: var(--muted);
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

img {
  max-width: 100%;
  height: auto;
}

/* =========================
   Layout
   ========================= */
.layout {
  display: grid;
  grid-template-rows: 3.5rem 1fr auto;
  /* header 56px */
  grid-template-columns: var(--sidebar-w) 1fr;
  grid-template-areas:
    "topbar topbar"
    "sidebar content"
    "footer footer";
}

/* Top bar (sticky/visible) */
.topbar {
  grid-area: topbar;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background: var(--bar);
  color: var(--barfg);
  padding: 0 1rem;
  position: sticky;
  top: 0;
  z-index: 1102;
  /* above sidebar/overlay */
}

.topbar .brand {
  font-size: var(--font-3);
  margin: 0;
  flex: 0 0 auto;
  font-family: Helvetica, "Helvetica Neue", Arial, system-ui, sans-serif;
  font-weight: 700;
  position: relative;
}

/* Brand underline highlight */
.topbar .brand::after {
  content: "";
  position: absolute;
  left: .3rem;
  right: .3rem;
  bottom: -.25rem;
  height: .2rem;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), #02bfe7);
  pointer-events: none;
}

.topbar .brand a {
  color: var(--barfg);
  text-decoration: none;
}

.topbar .topnav {
  margin-left: auto;
  display: flex;
  gap: 0.5rem;
}

.topbar .topnav a {
  display: inline-block;
  color: var(--barfg);
  text-decoration: none;
  font-weight: 600;
  padding: 0.375rem 0.625rem;
  border-radius: 0.375rem;
  transition: background .15s ease, color .15s ease;
}

.topbar .topnav a:hover,
.topbar .topnav a:focus-visible {
  background: rgba(255, 255, 255, .16);
  outline: none;
}

.topbar .topnav a.active,
.topbar .topnav a[aria-current="page"] {
  background: rgba(255, 255, 255, .10);
  border-bottom: 2px solid #fff;
  font-weight: 700;
}

/* Mobile menu button */
.menu-btn {
  display: none;
  background: transparent;
  border: 0;
  color: var(--barfg);
  font-size: 3rem;
  cursor: pointer;
}

.menu-btn.open {
  background: rgba(255, 255, 255, .16);
  border-radius: 0.375rem;
}

/* Sidebar */
.sidebar,
#sidebar {
  grid-area: sidebar;
  height: 100%;
  overflow: auto;
  background: var(--side);
  padding: 0.75rem;
  will-change: transform;
}

.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: #fff;
}

.sidebar .group {
  margin: 0.75rem 0;
}

.group-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0.5rem 0;
  font-weight: 700;
  letter-spacing: .04em;
}

/* Sidebar links like topbar */
.sidebar a {
  display: block;
  color: var(--barfg);
  text-decoration: none;
  font-weight: 600;
  padding: 0.375rem 0.625rem;
  border-radius: 0.375rem;
  transition: background .15s ease, color .15s ease;
}

.sidebar a:hover,
.sidebar a:focus-visible {
  background: rgba(255, 255, 255, .16);
  outline: none;
}

.sidebar a.active,
.sidebar a[aria-current="page"] {
  background: rgba(255, 255, 255, .10);
  border-bottom: 2px solid #fff;
  font-weight: 700;
}

/* Content + Footer */
.content {
  grid-area: content;
  padding: var(--space-3);
  min-width: 0;
}

.footer {
  grid-area: footer;
  background: var(--bar);
  color: var(--barfg);
  padding: 0.75rem;
  text-align: center;
  font-size: 0.75rem;
}

/* =========================
   Buttons
   ========================= */
.button {
  display: inline-block;
  padding: 0.5625rem 1rem;
  border-radius: 0.25rem;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  transition: filter .15s ease, transform .05s ease, background .2s ease, color .2s ease;
}

.button:hover {
  filter: brightness(.95);
}

.button:active {
  transform: translateY(1px);
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.button.secondary {
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
}

.button.secondary.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.button.secondary:hover {
  background: var(--accent);
  color: #fff;
}

.button.danger {
  background: var(--accent-warm);
  border-color: var(--accent-warm);
  color: #fff;
}

.button.danger:hover {
  filter: brightness(.9);
}

.button.muted {
  background: var(--nasa-gray-dark);
  border-color: var(--nasa-gray-dark);
  color: #fff;
}

.button.muted:hover {
  background: var(--nasa-gray);
  border-color: var(--nasa-gray);
}

.button.outline {
  background: transparent;
  border: 2px solid var(--accent);
  color: var(--accent);
}

.button.outline:hover {
  background: var(--accent);
  color: #fff;
}

.button.success {
  background: var(--nasa-accent-green);
  border-color: var(--nasa-accent-green);
  color: #fff;
}

.button.success:hover {
  filter: brightness(.95);
}

/* =========================
   Cards, Panels, Tables, Code — DARK (no shadows)
   ========================= */
.cards {
  display: grid;
  gap: 1rem;
}

@media (min-width: 56.25rem) {
  .cards.two {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .cards.three {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.card {
  background: var(--elev-1);
  color: var(--fg);
  border: 1px solid var(--border);
  border-top: 0.375rem solid var(--nasa-blue-light);
  border-radius: 0.625rem;
  overflow: hidden;
  box-shadow: none;
}

.card-output {
  border-top-color: var(--nasa-accent-gold);
  /* orange/gold */
}

.card .card__header {
  padding: 0.875rem 1rem;
  font-weight: 700;
  border-bottom: 1px solid var(--border);
}

.card .card__body {
  padding: 1rem;
}

.card .card__footer {
  padding: 0.75rem 1rem;
  border-top: 1px solid var(--border);
}

.panel {
  background: var(--elev-2);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.875rem;
  box-shadow: none;
}

/* Tables & code inside cards/panels */
.card table,
.panel table {
  width: 100%;
  border-collapse: collapse;
  table-layout: fixed;
  font-size: .95rem;
}

.card thead th,
.panel thead th {
  background: var(--elev-2);
  color: #fff;
  font-weight: 700;
  border-bottom: 1px solid var(--border);
}

.card th,
.card td,
.panel th,
.panel td {
  text-align: left;
  padding: 12px 14px;
  vertical-align: top;
  border-top: 1px solid var(--border);
}

.card code,
.panel code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
  font-size: .95rem;
  background: #16181f;
  color: #e5e7eb;
  padding: 0 .35em;
  border: 1px solid #2d3343;
  border-radius: 3px;
}

.card pre,
.panel pre {
  background: var(--code-bg);
  color: #e5e7eb;
  padding: 14px;
  border-radius: 8px;
  overflow: auto;
  border: 1px solid var(--code-stroke);
}

/* Remove decorative shadows globally */
.topbar,
.sidebar {
  box-shadow: none;
}

/* =========================
   Mobile drawer — FULL REMAINING HEIGHT UNDER HEADER
   ========================= */
@media (max-width: 56.25rem) {

  /* <= 900px */
  .layout {
    grid-template-columns: 1fr;
    grid-template-areas: "topbar" "content" "footer";
  }

  .menu-btn {
    display: inline-block;
  }

  /* show burger on mobile */
  .topbar .topnav {
    display: none;
  }

  /* hide horizontal nav */

  /* Full-width drawer that starts below the sticky header */
  .sidebar,
  #sidebar {
    position: fixed;
    inset: 3.5rem 0 0 0;
    /* below 56px header */
    height: calc(100vh - 3.5rem);
    transform: translateX(-100%);
    z-index: 1101;
    /* below header (1102), above overlay (1100) */
    overflow-y: auto;
    background: var(--side);
    border: 0;
    padding-left: max(0.75rem, env(safe-area-inset-left));
    padding-right: max(0.75rem, env(safe-area-inset-right));
    padding-bottom: max(0.75rem, env(safe-area-inset-bottom));
  }

  .sidebar.open,
  #sidebar.open {
    transform: translateX(0);
  }

  /* Modern viewport units for mobile browsers */
  @supports (height: 100dvh) {

    .sidebar,
    #sidebar {
      height: calc(100dvh - 3.5rem);
    }
  }

  /* Optional overlay that also respects header */
  .overlay {
    position: fixed;
    inset: 3.5rem 0 0 0;
    z-index: 1100;
  }
}

/* =========================
   Accessibility & Reduced motion
   ========================= */
a:focus-visible,
button:focus-visible,
[role="button"]:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--nasa-accent-cyan);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
    scroll-behavior: auto !important;
  }
}

/* =========================
   Utility: body scroll lock when menu is open (toggle via JS)
   ========================= */
body.menu-open {
  overflow: hidden;
  touch-action: none;
}

/* Final hammer — make validation borders win over everything */
.calc-form input.is-invalid,
.calc-form input.is-invalid:focus {
  border: 2px solid #d32f2f !important;
  background-color: #1a0000 !important;
  box-shadow: none !important;
}

.calc-form input.is-valid,
.calc-form input.is-valid:focus {
  border: 2px solid #2e7d32 !important;
  background-color: #001a09 !important;
  box-shadow: none !important;
}