:root {
  /* Core Theme Colors */
  --bg: #0f172a;
  --card-bg: #1e293b;
  --toolbar-bg: #111827;
  --border: #334155;
  --text: #f8fafc;
  --text-muted: #94a3b8;

  /* Brand / State Colors */
  --primary: #38bdf8;
  --primary-hover: #0284c7;
  --success: #34d399;
  --success-hover: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --danger-hover: #dc2626;

  /* Geometry & Elevation */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 14px;
  --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.4);
}

/* Light Theme Variable Overrides */
body.light-mode {
  --bg: #f0f2f5;
  --card-bg: #ffffff;
  --toolbar-bg: #f9fafb;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --primary: #0284c7;
  --primary-hover: #0369a1;
  --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.08);
}

/* Base Reset & Typography */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  background-color: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
  transition: background-color 0.2s ease, color 0.2s ease;
}

/* Containers & Cards */
.card, .container-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

/* Form Controls */
input:not([type="checkbox"]):not([type="radio"]):not([type="range"]),
select {
  background-color: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  font-size: 0.95rem;
  outline: none;
  transition: border-color 0.2s, background-color 0.2s;
  width: 100%;
}

input:not([type="checkbox"]):not([type="radio"]):not([type="range"]):focus,
select:focus {
  border-color: var(--primary);
}

/* Native Buttons */
button {
  background-color: var(--toolbar-bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 8px 14px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  outline: none;
  transition: background-color 0.2s, border-color 0.2s, transform 0.1s, opacity 0.2s;
}

button:hover:not(:disabled) {
  background-color: var(--border);
}

button:active:not(:disabled) {
  transform: translateY(1px);
}

button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

/* Button Variants */
.btn-primary {
  background-color: var(--primary);
  color: #0f172a;
  border-color: transparent;
}
.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
  color: #ffffff;
}

.btn-success {
  background-color: var(--success);
  color: #0f172a;
  border-color: transparent;
}
.btn-success:hover:not(:disabled) {
  background-color: var(--success-hover);
}

.btn-danger {
  background-color: var(--danger);
  color: #ffffff;
  border-color: transparent;
}
.btn-danger:hover:not(:disabled) {
  background-color: var(--danger-hover);
}

/* Form Helpers: Checkbox, File Uploads, Range */
.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--text-muted);
  user-select: none;
}
.checkbox-label input[type="checkbox"] {
  accent-color: var(--primary);
  cursor: pointer;
  width: 16px;
  height: 16px;
}
.checkbox-label:hover {
  color: var(--text);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--primary);
  cursor: pointer;
}

.upload-btn {
  background-color: var(--primary);
  color: #0f172a;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: var(--radius-md);
  cursor: pointer;
  font-size: 0.9rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  user-select: none;
  transition: background-color 0.2s ease;
}
.upload-btn:hover {
  background-color: var(--primary-hover);
  color: #ffffff;
}
input[type="file"] {
  display: none;
}

/* Global Footer */
footer.site-footer {
  text-align: center;
  margin-top: 2.5rem;
  padding-bottom: 1.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

footer.site-footer a {
  color: var(--primary);
  text-decoration: none;
}

footer.site-footer a:hover {
  text-decoration: underline;
}