/* --- Light Mode Variables --- */
body[data-theme="light"] {
  --bg: #f4f5f7;
  --card: #ffffff;
  --text-main: #121212;
  --text-muted: #555;
  --accent: #007bff;
  --danger: #dc3545;
  --border: #dee2e6;
  --input-bg: #f8f9fa;
  --accent-bg: #e6f2ff;
  --accent-flash: #007bff;
  --card-flash: #ffffff;
  --shadow-color: rgba(0, 0, 0, 0.1);
}

/* --- Dark Mode Variables --- */
body[data-theme="dark"] {
  --bg: #121212;
  --card: #1f1f1f;
  --text-main: #f2f2f2;
  --text-muted: #999;
  --accent: #00aaff;
  --danger: #ff5050;
  --border: #2a2a2a;
  --input-bg: #0e0e0e;
  --accent-bg: #00aaff1a;
  --accent-flash: #00aaff;
  --card-flash: #1f1f1f;
  --shadow-color: rgba(0, 0, 0, 0.3);
}

:root {
  /* Default font size */
  font-size: 16px;
}

/* --- Font Size Scaling --- */
body[data-font-size="xs"] { font-size: 14px; }
body[data-font-size="sm"] { font-size: 15px; }
body[data-font-size="md"] { font-size: 16px; }
body[data-font-size="lg"] { font-size: 18px; }
body[data-font-size="xl"] { font-size: 20px; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg);
  color: var(--text-main);
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  padding: 2rem 0;
  transition: background-color 0.2s ease, color 0.2s ease, font-size 0.2s ease;
}

main {
  background: var(--card);
  max-width: 760px;
  width: 90%;
  padding: 1.5rem 2rem 2rem 2rem;
  border-radius: 12px;
  box-shadow: 0 0 25px var(--shadow-color);
  transition: background-color 0.2s ease;
}

.main-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  gap: 1rem;
  flex-wrap: wrap;
}

h1 {
  text-align: left;
  color: var(--accent);
  margin: 0;
  font-size: 1.75rem;
}

h2 {
  text-align: center;
  color: var(--accent);
  margin-top: 0;
}

/* --- Header Controls (Theme + Font) --- */
.controls-group {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.font-size-control {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
}
.font-size-control button {
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 0.25rem 0.5rem;
  cursor: pointer;
  line-height: 1;
  font-size: 1rem;
  margin: 0;
  box-sizing: border-box; /* Ensures padding/border don't change height */
}
.font-size-control button:hover {
  background: var(--input-bg);
  color: var(--text-main);
  filter: none;
}
.font-size-control button:first-child {
  border-right: 1px solid var(--border);
}


.theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.theme-toggle svg {
  color: var(--text-muted);
}
.toggle-switch {
  position: relative;
  display: inline-block;
  width: 38px;
  height: 20px;
}
.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}
.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border);
  transition: .2s;
  border-radius: 20px;
}
.slider:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .2s;
  border-radius: 50%;
}
input:checked + .slider {
  background-color: var(--accent);
}
input:checked + .slider:before {
  transform: translateX(18px);
}

/* --- Global Gamma --- */
.global-settings {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
  background-color: var(--input-bg);
  padding: 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  margin-bottom: 1.5rem;
}
.global-settings label {
  font-weight: 600;
  color: var(--text-muted);
}
.global-settings input {
  font-family: inherit;
  font-size: 1rem;
  color: var(--text-main);
  background-color: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  width: 70px;
  padding: 0.25rem 0.5rem;
  margin: 0;
}

/* --- Navigation --- */
.calculator-nav {
  display: flex;
  border-bottom: 2px solid var(--border);
  margin-bottom: 2rem;
  flex-wrap: wrap;
}
.nav-btn {
  padding: 0.75rem 1rem;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 1rem; /* Scales with body font size */
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  flex-basis: 0;
  flex-grow: 1;
  text-align: center;
}
/* Make 5th button wrap nicely */
.nav-btn:nth-child(5) {
  flex-grow: 0;
  min-width: 100%;
}


.nav-btn:hover {
  color: var(--text-main);
}
.nav-btn.active {
  color: var(--accent);
  border-bottom: 3px solid var(--accent);
}

/* --- Panels --- */
.calculator-panel { display: none; }
.calculator-panel.active { display: block; animation: fadeIn 0.3s ease; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* --- Input Section --- */
.input-section {
  background-color: var(--input-bg);
  padding: 1rem 1.25rem;
  border-radius: 10px;
  border: 1px solid var(--border);
}
.input-hint {
  font-size: 0.9rem;
  color: var(--text-muted);
  text-align: center;
  margin-top: 0;
}
.input-row {
  display: flex;
  flex-direction: column;
  margin-top: 1rem;
}
.input-row:first-child { margin-top: 0; }

label {
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 0.25rem;
}

input, select {
  padding: 0.5rem;
  border-radius: 6px;
  border: 1px solid var(--border);
  background-color: var(--bg);
  color: var(--text-main);
  font-family: inherit;
  font-size: 1rem;
  transition: border-color 0.2s ease;
  box-sizing: border-box; /* Ensures padding/border don't change height */
}
input:focus, select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-bg);
}

/* --- Calculated Input Style --- */
input.is-calculated-input {
  border-color: var(--accent);
  background-color: var(--accent-bg);
  font-weight: 600;
}

/* --- Buttons --- */
button {
  margin-top: 1.2rem;
  padding: 0.6rem;
  width: 100%;
  border: 1px solid transparent; /* Ensures consistent height */
  background: var(--accent);
  color: #fff;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s ease;
  box-sizing: border-box; /* Ensures padding/border don't change height */
}
button:hover {
  filter: brightness(1.1);
}

.button-group {
    display: flex;
    gap: 0.75rem;
    margin-top: 1.2rem;
}
.button-group .btn-secondary {
    background: transparent;
    border-color: var(--text-muted); /* Use border-color instead of border */
    color: var(--text-muted);
    flex-grow: 1;
}
.button-group .btn-primary {
    margin-top: 0;
    border-color: var(--accent); /* Use border-color */
    flex-grow: 1;
}

.warning {
  color: var(--danger);
  min-height: 1.2em;
  font-size: 0.9rem;
  margin-top: 0.5rem;
  text-align: center;
}

/* --- Results --- */
.results {
  margin-top: 1.5rem;
  background-color: var(--input-bg);
  padding: 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
}
.results-table {
  display: flex;
  flex-direction: column;
}
.results-table .row {
  display: flex;
  justify-content: space-between;
  padding: 0.4rem 0.3rem;
  border-bottom: 1px solid var(--border);
  border-radius: 3px;
  /* Add margin/padding compensation to allow flash to fill row */
  margin: 0 -0.3rem;
  padding: 0.4rem 0.6rem;
}
.results-table .row:last-child {
  border-bottom: none;
}
.results-table .label {
  color: var(--text-muted);
}
.results-table .value {
  font-family: monospace;
  font-weight: 600;
  color: var(--accent);
}

/* --- Result Flash Animation --- */
.is-new-result-row {
  animation: flash-row 0.8s ease-out;
}
@keyframes flash-row {
  0% { 
    background-color: var(--accent-flash);
  }
  30% { 
    background-color: var(--accent-flash);
  }
  100% { 
    background-color: transparent;
  }
  /* Ensure text color is readable during flash */
  0% .label, 30% .label {
    color: var(--card-flash);
  }
  0% .value, 30% .value {
    color: var(--card-flash);
  }
  100% .label {
    color: var(--text-muted);
  }
  100% .value {
    color: var(--accent);
  }
}

/* --- Wedge Airfoil Specific --- */
#wa-results-upper-shock,
#wa-results-upper-exp,
#wa-results-upper-aligned {
  display: none; /* JS will show the correct one */
}

/* --- Diagrams --- */
.diagram-section {
  margin-top: 2rem;
  text-align: center;
}
svg {
  max-width: 100%;
  height: auto;
  margin-top: 1rem;
}
#ob-shockDiagram, #wa-diagram {
  margin-top: 0; /* Position diagram just under title */
}
svg text {
  font-family: system-ui, sans-serif;
  dominant-baseline: middle;
  text-anchor: middle;
  user-select: none;
}
#ob-thetaLabel, #ob-betaLabel {
    text-anchor: start;
}
.diagram-caption {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

/* --- Footer --- */
footer {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.8rem;
  color: var(--text-muted);
  max-width: 760px;
  width: 90%;
}