*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0f1117;
  --surface:   #1a1d27;
  --card:      #20242f;
  --border:    #2e3347;
  --accent:    #4f8ef7;
  --accent2:   #f7854f;
  --accent3:   #4fcf8e;
  --text:      #e4e8f0;
  --muted:     #8892a4;
  --danger:    #f74f4f;
  --radius:    10px;
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
}

/* ── Header ── */
header {
  background: linear-gradient(135deg, #1a1d27 0%, #16213e 100%);
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}
.header-title { text-align: center; }
header h1 {
  font-size: clamp(1.05rem, 3.5vw, 1.4rem);
  font-weight: 700;
  letter-spacing: -0.02em;
}
header p {
  font-size: clamp(0.72rem, 2vw, 0.8rem);
  color: var(--muted);
  margin-top: 0.1rem;
}

/* ── PDF Export Button ── */
.btn-export-pdf {
  position: absolute;
  right: 2rem;
  top: 50%;
  transform: translateY(-50%);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.20);
  color: #e4e8f0;
  font-size: 0.82rem;
  font-weight: 600;
  padding: 0.5rem 1rem;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  white-space: nowrap;
}
.btn-export-pdf:hover {
  background: rgba(255,255,255,0.15);
  border-color: rgba(255,255,255,0.40);
}
.btn-export-pdf:active { transform: translateY(-50%) scale(0.97); }
.pdf-badge {
  font-size: 0.62rem;
  font-weight: 800;
  background: #e53935;
  color: #fff;
  padding: 0.1rem 0.32rem;
  border-radius: 3px;
  letter-spacing: 0.04em;
}

/* ── Layout ── */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: clamp(1rem, 2.5vw, 2rem) clamp(0.75rem, 2.5vw, 1.5rem);
  display: grid;
  grid-template-columns: clamp(280px, 29%, 340px) 1fr;
  gap: clamp(0.75rem, 1.5vw, 1.5rem);
  align-items: start;
}
@media (max-width: 820px) {
  .container { grid-template-columns: 1fr; }
}

/* ── Cards ── */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.card-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--muted);
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}

/* ── Card header (title + action button row) ── */
.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border);
}
.card-header .card-title {
  margin-bottom: 0;
  border-bottom: none;
  padding-bottom: 0;
}

/* inline card title (inside table-controls row) */
.card-title--inline {
  margin-bottom: 0;
  border-bottom: none;
  padding-bottom: 0;
}

/* ── Form ── */
.field { margin-bottom: 1.1rem; }
label {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 0.35rem;
}
input, select {
  width: 100%;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.95rem;
  padding: 0.55rem 0.75rem;
  outline: none;
  transition: border-color 0.15s;
}
input:focus, select:focus { border-color: var(--accent); }
input.error { border-color: var(--danger); }
.field-hint {
  font-size: 0.73rem;
  color: var(--muted);
  margin-top: 0.25rem;
}
.field-error {
  font-size: 0.73rem;
  color: var(--danger);
  margin-top: 0.25rem;
  display: none;
}
.field-error.visible { display: block; }

/* terrain badge */
.terrain-badge {
  display: inline-block;
  font-size: 0.7rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.15rem 0.45rem;
  color: var(--muted);
  margin-top: 0.3rem;
}
.terrain-badge span { color: var(--accent); font-weight: 600; }

/* action row (Calculate button wrapper) */
.action-row { margin-top: 0.5rem; }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.6rem 1.1rem;
  border-radius: 6px;
  border: none;
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 600;
  transition: opacity 0.15s, transform 0.1s;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--accent);
  color: #fff;
  width: 100%;
  justify-content: center;
  padding: 0.7rem;
  font-size: 0.95rem;
}
.btn-primary:hover { opacity: 0.88; }

.btn-secondary {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-secondary:hover { border-color: var(--accent); color: var(--accent); }

.btn-reset {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.82rem;
  padding: 0.35rem 0.75rem;
}
.btn-reset:hover { border-color: var(--accent2); color: var(--accent2); }

.btn-flip {
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.82rem;
  padding: 0.35rem 0.75rem;
}
.btn-flip:hover { border-color: var(--accent); color: var(--accent); }

/* ── Results area ── */
.results-area { display: flex; flex-direction: column; gap: 1.5rem; }

.placeholder {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  min-height: 300px;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
}
.placeholder .big-icon { font-size: 3rem; opacity: 0.4; }

/* ── Stats row ── */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
  gap: 0.75rem;
}
.stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.9rem 1rem;
  text-align: center;
}
.stat-value { font-size: clamp(1.1rem, 3vw, 1.5rem); font-weight: 700; }
.stat-label { font-size: 0.7rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.06em; margin-top: 0.15rem; }
.stat-value.log  { color: var(--accent); }
.stat-value.pow  { color: var(--accent2); }
.stat-value.avg  { color: var(--accent3); }
.stat-value--terrain { color: var(--text); font-size: 0.95rem; padding-top: 0.3rem; }

/* ── Chart ── */
.chart-wrap {
  position: relative;
  width: 100%;
  min-width: 0;
  height: clamp(240px, 40vh, 340px);
}

/* Prevent grid/flex children from overflowing their tracks */
.container > *,
.results-area > * { min-width: 0; }

/* ── Legend chips ── */
.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 0.75rem;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.2rem 0.65rem;
}
.chip-dot { width: 8px; height: 8px; border-radius: 50%; }
.chip-dot--low      { background: #f7854f; }
.chip-dot--expected { background: #4fcf8e; }
.chip-dot--high     { background: #4f8ef7; }

/* Max Flight Alt chip (dashed line swatch) */
.chip-line {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.75rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 0.2rem 0.65rem;
}
.chip-dash {
  width: 18px;
  height: 2px;
  background: repeating-linear-gradient(
    90deg,
    rgba(247,79,79,0.85) 0,
    rgba(247,79,79,0.85) 5px,
    transparent 5px,
    transparent 9px
  );
}

/* ── Table ── */
.table-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}
.export-btns { display: flex; gap: 0.5rem; }

.table-scroll {
  overflow-x: auto;
  border-radius: 8px;
  border: 1px solid var(--border);
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.84rem;
}
thead tr { background: var(--surface); }
th {
  padding: 0.65rem 0.85rem;
  text-align: right;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
th:first-child { text-align: left; }
td {
  padding: 0.55rem 0.85rem;
  text-align: right;
  border-bottom: 1px solid var(--border);
}
td:first-child { text-align: left; font-weight: 600; }
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: rgba(255,255,255,0.03); }

/* Reference altitude row */
.ref-row td { background: rgba(79,142,247,0.08); }
.ref-row td:first-child::after { content: ' ★'; color: var(--accent); font-size: 0.7em; }

/* Ceiling row */
.ceiling-row td { background: rgba(247,133,79,0.05); }
.ceiling-row td:first-child::after { content: ' ▲'; color: var(--accent2); font-size: 0.7em; }

/* Column colours */
.col-log  { color: var(--accent); }
.col-pow  { color: var(--accent2); }
.col-avg  { color: var(--accent3); }
.col-diff { color: var(--muted); }
.diff-pos { color: #f7c54f; }
.diff-neg { color: #c87fff; }

/* Status column */
.status-safe    { color: #4fcf8e; font-weight: 700; text-align: center; }
.status-caution { color: #f7c54f; font-weight: 700; text-align: center; }
.status-exceeds { color: var(--danger); font-weight: 700; text-align: center; }
.status-neutral { color: var(--muted); text-align: center; }

/* ── Unit toggle ── */
.unit-toggle {
  display: flex;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 3px;
  gap: 3px;
}
.unit-toggle input[type="radio"] { display: none; }
.unit-toggle label {
  flex: 1;
  text-align: center;
  padding: 0.4rem 0.5rem;
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--muted);
  margin: 0;
  transition: background 0.15s, color 0.15s;
  white-space: nowrap;
}
.unit-toggle input[type="radio"]:checked + label {
  background: var(--accent);
  color: #fff;
}

/* ── Safety Caution ── */
.safety-caution {
  display: flex;
  gap: 1rem;
  background: rgba(247,133,79,0.08);
  border: 1px solid rgba(247,133,79,0.3);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
}
.caution-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
}
.caution-body { flex: 1; }
.caution-title {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--accent2);
  margin-bottom: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.caution-body p {
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.65;
}
.caution-body strong { color: var(--text); }

/* ── Legal Disclaimer ── */
.legal-section {
  max-width: 1200px;
  margin: 0 auto 2rem;
  padding: 0 1.5rem;
}
.legal-details {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.legal-summary {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.9rem 1.25rem;
  cursor: pointer;
  user-select: none;
  list-style: none;
}
.legal-summary::-webkit-details-marker { display: none; }
.legal-summary-icon {
  color: var(--accent2);
  font-size: 1rem;
  flex-shrink: 0;
}
.legal-summary-text {
  flex: 1;
  font-size: 0.82rem;
  color: var(--muted);
}
.legal-chevron {
  color: var(--muted);
  font-size: 0.75rem;
  transition: transform 0.2s;
}
details[open] .legal-chevron { transform: rotate(180deg); }
.legal-body {
  padding: 0 1.25rem 1.25rem;
  border-top: 1px solid var(--border);
}
.legal-body p {
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.65;
  margin-top: 0.85rem;
}
.legal-body strong { color: var(--text); }
.legal-body em { color: var(--accent2); font-style: normal; }

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--surface); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ── Drone limit zone legend chips ── */
.legend--zones { margin-top: 0.4rem; }
.chip-band { width: 14px; height: 8px; border-radius: 2px; flex-shrink: 0; }
.chip-band--safe    { background: rgba(79,207,142,0.35); border: 1px solid rgba(79,207,142,0.65); }
.chip-band--caution { background: rgba(247,197,79,0.35);  border: 1px solid rgba(247,197,79,0.65);  }
.chip-band--exceed  { background: rgba(247,79,79,0.35);   border: 1px solid rgba(247,79,79,0.65);   }

/* ── Drone limit info bar ── */
.drone-limit-info {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.72rem;
  color: var(--muted);
  min-height: 1.2rem;
  margin-bottom: 0.5rem;
}
.drone-limit-info .dlabel { color: var(--text); font-weight: 600; }
.drone-limit-info .dsep   { color: var(--border); }
.drone-limit-info .dzone  { font-weight: 600; }
.dzone--safe    { color: #4fcf8e; }
.dzone--caution { color: #f7c54f; }
.dzone--exceed  { color: var(--danger); }

/* ── Drone warning banner ── */
.drone-warning {
  display: flex;
  gap: 1rem;
  background: rgba(247,79,79,0.10);
  border: 1px solid rgba(247,79,79,0.55);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  animation: drone-warn-pulse 1.8s ease-in-out infinite;
}
@keyframes drone-warn-pulse {
  0%, 100% { border-color: rgba(247,79,79,0.45); background: rgba(247,79,79,0.08); }
  50%       { border-color: rgba(247,79,79,0.90); background: rgba(247,79,79,0.16); }
}
.drone-warning-icon { font-size: 1.5rem; flex-shrink: 0; }
.drone-warning-body { flex: 1; }
.drone-warning-title {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--danger);
  margin-bottom: 0.4rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.drone-warning-body p { font-size: 0.78rem; color: var(--text); line-height: 1.65; }
.drone-warning-body strong { color: var(--danger); }

/* ════════════════════════════════════════════════════════════════
   RESPONSIVE BREAKPOINTS
   ════════════════════════════════════════════════════════════════ */

/* ── Large tablet / small desktop (≤ 1024px) ── */
@media (max-width: 1024px) {
  .card { padding: 1.25rem; }
  .card-title  { margin-bottom: 1rem; padding-bottom: 0.65rem; }
  .card-header { margin-bottom: 1rem; padding-bottom: 0.65rem; }
}

/* ── Tablet / large mobile (≤ 640px) ── */
@media (max-width: 640px) {
  .card { padding: 1rem; }
  .card-title  { margin-bottom: 0.9rem; padding-bottom: 0.55rem; }
  .card-header { margin-bottom: 0.9rem; padding-bottom: 0.55rem; }
  .results-area { gap: 1rem; }

  /* Touch-friendly minimum heights */
  .btn          { min-height: 40px; font-size: 0.85rem; }
  .btn-primary  { min-height: 44px; padding: 0.75rem; font-size: 0.9rem; }
  .btn-secondary, .btn-reset, .btn-flip { min-height: 36px; }

  /* Stats */
  .stats-row { gap: 0.5rem; }
  .stat      { padding: 0.75rem 0.65rem; }

  /* Table */
  table { font-size: 0.8rem; }
  th    { padding: 0.55rem 0.65rem; font-size: 0.66rem; }
  td    { padding: 0.5rem  0.65rem; }

  /* Legal / caution text scale */
  .legal-section { padding: 0 0.75rem; margin-bottom: 1.25rem; }
  .legal-summary { padding: 0.75rem 1rem; }
  .legal-body    { padding: 0 1rem 1rem; }
  .legal-body p,
  .caution-body p { font-size: 0.76rem; }
}

/* ── Mobile portrait (≤ 480px) ── */
@media (max-width: 480px) {
  /* Header: stack title above export button */
  header {
    flex-direction: column;
    align-items: center;
    padding: 0.85rem 1rem;
    gap: 0.5rem;
  }
  .btn-export-pdf {
    position: static;
    transform: none;
    font-size: 0.78rem;
    padding: 0.42rem 0.9rem;
  }
  .btn-export-pdf:active { transform: scale(0.97); }

  /* Layout */
  .container    { padding: 0.75rem; }
  .card         { padding: 0.9rem; }
  .results-area { gap: 0.9rem; }

  /* Chart */
  .chart-wrap { height: 260px; }
  .legend     { gap: 0.35rem; margin-bottom: 0.5rem; }
  .chip, .chip-line { font-size: 0.68rem; padding: 0.15rem 0.5rem; }
  .legend--zones    { margin-top: 0.3rem; }

  /* Stats: 2-column grid */
  .stats-row { grid-template-columns: repeat(2, 1fr); gap: 0.45rem; }
  .stat      { padding: 0.7rem 0.5rem; }
  .stat-label { font-size: 0.62rem; letter-spacing: 0.03em; }

  /* Placeholder */
  .placeholder          { min-height: 180px; font-size: 0.82rem; }
  .placeholder .big-icon { font-size: 2rem; }

  /* Form inputs */
  .field   { margin-bottom: 0.85rem; }
  input, select { padding: 0.6rem 0.65rem; font-size: 0.9rem; }

  /* Stack icon + body in banner components */
  .safety-caution,
  .drone-warning { flex-direction: column; gap: 0.4rem; padding: 0.85rem 1rem; }
  .caution-icon,
  .drone-warning-icon { font-size: 1.25rem; }

  /* Drone limit bar */
  .drone-limit-info { font-size: 0.67rem; gap: 0.3rem; }

  /* Legal */
  .legal-section { padding: 0 0.5rem; }
}

/* ── Small phones (≤ 360px) ── */
@media (max-width: 360px) {
  header h1 { font-size: 0.95rem; }
  header p  { font-size: 0.68rem; }

  .unit-toggle label { font-size: 0.72rem; padding: 0.35rem 0.25rem; }

  .chart-wrap { height: 220px; }

  .stat-value { font-size: 1rem; }
  .stat-label { font-size: 0.6rem; }

  th { font-size: 0.62rem; padding: 0.45rem 0.4rem; }
  td { font-size: 0.75rem; padding: 0.4rem  0.4rem; }

  .btn-primary { font-size: 0.85rem; }
  .card        { padding: 0.75rem; }
}

/* ── Landscape phones: restore a bit of chart height ── */
@media (max-width: 640px) and (orientation: landscape) {
  .chart-wrap { height: 200px; }
  header      { padding: 0.6rem 1rem; gap: 0.3rem; }
  header h1   { font-size: 1rem; }
}