/* --- 1. Global Styles & Theming --- */
:root {
   /* Color Palette */
   --color-primary: #3498db;
   --color-secondary: #2c3e50;
   --color-danger: #e74c3c;
   --color-success: #1abc9c;
   --color-warning: #f1c40f;
   --color-info: #9b59b6;
   --color-special: #e67e22;

   /* Light Theme */
   --bg-page: #ffffff;
   --bg-controls: #f8f9fa;
   --bg-visualizer: #ecf0f1;
   --bg-code: #f1f1f1;
   --bg-code-inline: rgba(0, 0, 0, 0.05);
   --bg-tooltip: var(--color-secondary);
   --bg-input: #ffffff;

   --text-body: #333333;
   --text-heading: var(--color-secondary);
   --text-code: #333333;
   --text-tooltip: #ffffff;
   --text-input: #000000;
   --text-label-selected: var(--color-danger);

   --border-main: #dee2e6;
   --border-visualizer: var(--color-primary);
   --border-input: #cccccc;

   --shadow-main: 0 4px 12px rgba(0, 0, 0, 0.05);

   --code-comment: #6a737d;
   --code-property: #005cc5;
   --code-value: #d73a49;
}

@media (prefers-color-scheme: dark) {
   :root {
      /* Dark Theme */
      --bg-page: #1a202c;
      --bg-controls: #2d3748;
      --bg-visualizer: #2a2a33;
      --bg-code: #1e1e1e;
      --bg-code-inline: rgba(255, 255, 255, 0.1);
      --bg-tooltip: #4a5568;
      --bg-input: #2d3748;

      --text-body: #e2e8f0;
      --text-heading: #f7fafc;
      --text-code: #d4d4d4;
      --text-tooltip: #f7fafc;
      --text-input: #e2e8f0;
      --text-label-selected: #ff7575; /* Lighter red for dark bg */

      --border-main: #4a5568;
      --border-input: #4a5568;

      --shadow-main: 0 4px 12px rgba(0, 0, 0, 0.2);

      --code-comment: #888888;
      --code-property: #9cdcfe;
      --code-value: #ce9178;
   }
}

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

body {
   font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
   line-height: 1.7;
   background-color: var(--bg-page);
   color: var(--text-body);
   transition: background-color 0.2s ease, color 0.2s ease;
   padding-bottom: 50px;
}

.container {
   max-width: 1400px;
   margin: 0 auto;
   padding: 20px;
}

h1,
h2,
h3 {
   color: var(--text-heading);
   margin-bottom: 15px;
   line-height: 1.3;
}

h1 {
   font-size: 2.5rem;
   text-align: center;
   margin: 30px 0;
}

h2 {
   font-size: 2rem;
   border-bottom: 2px solid var(--color-primary);
   padding-bottom: 10px;
   margin-top: 40px;
}

h3 {
   font-size: 1.5rem;
   margin-top: 25px;
}

p {
   margin-bottom: 15px;
}

code {
   font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
   background-color: var(--bg-code-inline);
   color: var(--text-code);
   padding: 2px 5px;
   border-radius: 4px;
}

pre {
   background: var(--bg-code);
   color: var(--text-code);
   padding: 20px;
   border-radius: 8px; /* Consistent border radius */
   overflow-x: auto;
   margin-bottom: 20px;
   font-size: 0.9rem;
}

pre .comment {
   color: var(--code-comment);
}
pre .property {
   color: var(--code-property);
}
pre .value {
   color: var(--code-value);
}

button {
   cursor: pointer;
   padding: 8px 15px;
   border: none;
   border-radius: 5px;
   background-color: var(--color-primary);
   color: white;
   font-size: 0.9rem;
   font-weight: bold;
   transition: background-color 0.2s ease;
}

button:hover {
   opacity: 0.85;
}

button.danger {
   background-color: var(--color-danger);
}
button.secondary {
   background-color: var(--color-secondary);
}

/* --- 2. Tooltip Styles --- */
.tooltip {
   position: relative;
   display: inline-block;
   cursor: help;
   margin-left: 8px;
   font-size: 0.8rem;
   background: var(--bg-tooltip);
   color: var(--text-tooltip);
   border-radius: 50%;
   width: 18px;
   height: 18px;
   text-align: center;
   line-height: 18px;
   font-weight: bold;
}

.tooltip .tooltiptext {
   visibility: hidden;
   width: 250px;
   background-color: var(--bg-tooltip);
   color: var(--text-tooltip);
   text-align: left;
   border-radius: 6px;
   padding: 10px;
   position: absolute;
   z-index: 1;
   bottom: 150%;
   left: 50%;
   margin-left: -125px;
   opacity: 0;
   transition: opacity 0.3s;
   font-size: 0.85rem;
   font-weight: normal;
}

.tooltip .tooltiptext::after {
   content: "";
   position: absolute;
   top: 100%;
   left: 50%;
   margin-left: -5px;
   border-width: 5px;
   border-style: solid;
   border-color: var(--bg-tooltip) transparent transparent transparent;
}

.tooltip:hover .tooltiptext {
   visibility: visible;
   opacity: 1;
}

/* --- 3. Playground Layout --- */
.playground {
   display: grid;
   grid-template-columns: 350px 1fr;
   gap: 30px;
   margin-top: 30px;
}

.controls {
   background: var(--bg-controls);
   border: 1px solid var(--border-main);
   border-radius: 8px;
   padding: 25px;
   box-shadow: var(--shadow-main);
   height: fit-content;
}

.control-group {
   margin-bottom: 25px;
}

.control-group label {
   display: flex;
   align-items: center;
   font-weight: 600;
   margin-bottom: 8px;
   color: var(--text-heading);
}

.control-group select,
.control-group input {
   width: 100%;
   padding: 10px;
   border-radius: 5px;
   border: 1px solid var(--border-input);
   font-size: 0.95rem;
   background-color: var(--bg-input);
   color: var(--text-input);
}

.visualizer-wrapper {
   position: relative;
}

.visualizer-container {
   display: flex;
   min-height: 500px;
   background: var(--bg-visualizer);
   border: 2px dashed var(--border-visualizer);
   border-radius: 8px;
   padding: 15px;
   transition: all 0.3s ease;
}

.flex-item {
   /* Default item styles */
   display: flex;
   justify-content: center;
   align-items: center;
   background: var(--color-primary);
   color: white;
   font-size: 2rem;
   font-weight: bold;
   padding: 20px;
   border-radius: 5px;
   text-align: center;
   min-width: 80px;
   min-height: 80px;
   border: 3px solid rgba(0, 0, 0, 0.1);
   transition: all 0.3s ease;
   cursor: pointer;
}

.flex-item:hover {
   opacity: 0.8;
}

.flex-item.selected {
   background-color: var(--color-danger) !important;
   outline: 3px solid var(--color-danger);
   box-shadow: 0 0 15px rgba(231, 76, 60, 0.5);
   transform: scale(1.05);
   z-index: 10;
}

/* Colors for different items */
.flex-item:nth-child(2n) {
   background-color: var(--color-success);
}
.flex-item:nth-child(3n) {
   background-color: var(--color-info);
}
.flex-item:nth-child(4n) {
   background-color: var(--color-warning);
   color: #333;
}
.flex-item:nth-child(5n) {
   background-color: var(--color-special);
}

.item-controls-header {
   display: flex;
   justify-content: space-between;
   align-items: center;
   margin-bottom: 15px;
}

#selected-item-label {
   font-style: italic;
   color: var(--text-label-selected);
   font-weight: bold;
}

.item-manager-buttons {
   display: flex;
   gap: 10px;
   margin-top: 20px;
   margin-bottom: 20px;
}
.item-manager-buttons button {
   flex-grow: 1;
}

hr {
   margin: 30px 0;
   border: none;
   border-top: 1px solid var(--border-main);
}

/* --- 4. Challenges Section --- */
.challenges-grid {
   display: grid;
   grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
   gap: 20px;
}

.challenge-card {
   background: var(--bg-controls);
   border: 1px solid var(--border-main);
   border-radius: 8px;
   padding: 20px;
   box-shadow: var(--shadow-main);
}
.challenge-card h4 {
   color: var(--color-primary);
   font-size: 1.2rem;
   margin-bottom: 10px;
}
.challenge-card .solution {
   display: none;
   margin-top: 15px;
}

/* --- 5. Responsiveness --- */
@media (max-width: 992px) {
   .playground {
      grid-template-columns: 1fr;
   }

   .controls {
      /* Place controls before visualizer on mobile */
      order: 1;
   }

   .visualizer-wrapper {
      order: 2;
   }
}

@media (max-width: 768px) {
   h1 {
      font-size: 2rem;
   }
   h2 {
      font-size: 1.75rem;
   }
   .visualizer-container {
      min-height: 400px;
   }
}