:root {
    --bg-color: #282c34; /* Primary Background */
    --panel-bg: #1e2127; /* Secondary Background */
    --text-color: #abb2bf; /* Primary Text */
    --text-color-light: #c8ccd4; /* Lighter Text */
    --border-color: #444c56; /* Borders */
    --accent-color: #61afef; /* Primary Accent (Blue) */
    --accent-color-hover: #5295cf;
    --success-color: #98c379; /* Green Accent for Success */
    --success-color-hover: #80a965;
    --error-color: #e06c75; /* Red Accent for Errors */
    --error-color-hover: #c85861;
    --warning-color: #e5c07b; /* Yellow/Orange for Warnings */
    --button-bg: #4a505a; /* Default Button BG */
    --button-hover-bg: #5a616d;
    --input-bg: #3a3f4b; /* Input Background */
    --gutter-color: #4a505a;
    --tab-bg: #1e2127;
    --tab-active-bg: #3a3f4b;
    --tab-text: #888e9a;
    --tab-active-text: #abb2bf;
    --header-height: 56px;
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; /* System fonts */
    --font-mono: 'Consolas', 'Courier New', Courier, monospace; /* Mono fonts */
}
/* Modal styles for Learn More */
.modal {
  display: none; /* Hidden by default */
  position: fixed;
  z-index: 10000;
  left: 0;
  top: 0;
  width: 100vw;
  height: 100vh;
  overflow: auto;
  background: rgba(20, 20, 30, 0.85);
  transition: opacity 0.2s;
}

.modal-content {
  background: var(--panel-bg, #23232b);
  color: var(--text-primary, #f0f0f0);
  margin: 5% auto;
  padding: 2rem 2.5rem;
  border-radius: 10px;
  width: 95%;
  max-width: 540px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.35);
  position: relative;
  font-size: 1.08rem;
  line-height: 1.6;
}

.modal-content h2 {
  margin-top: 0;
  font-size: 1.5rem;
  color: var(--accent, #7ecfff);
}

.modal-content ul {
  margin: 1em 0 1em 1.5em;
  padding: 0;
}

.modal-content li {
  margin-bottom: 0.7em;
}

.modal-content code {
  background: #18181f;
  color: #7ecfff;
  padding: 0.1em 0.4em;
  border-radius: 4px;
  font-size: 0.98em;
}

.modal-content .close {
  position: absolute;
  right: 1.1em;
  top: 1.1em;
  font-size: 1.6em;
  color: var(--text-secondary, #aaa);
  cursor: pointer;
  transition: color 0.2s;
}

.modal-content .close:hover {
  color: var(--accent, #7ecfff);
}

@media (max-width: 600px) {
  .modal-content {
    padding: 1.1rem 0.7rem;
    font-size: 0.98rem;
  }
}
/* Basic Reset & Body */
html, body {
    height: 100%; margin: 0; padding: 0;
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 14px;
    overflow: hidden;
}
body { display: flex; flex-direction: column; }
* { box-sizing: border-box; }

/* App Structure */
.app-container { display: flex; flex-direction: column; height: 100vh; }
.header {
    height: var(--header-height);
    background: var(--panel-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 20px; flex-shrink: 0; position: sticky; top: 0; z-index: 100;
}
.main-content {
    display: flex; flex-grow: 1;
    height: calc(100vh - var(--header-height));
    opacity: 0; transition: opacity 0.2s ease-in-out;
}
.main-content.loaded { opacity: 1; }

/* Header Content */
.header .logo {
    font-size: 1.4em; font-weight: 700; color: var(--accent-color);
    display: flex; align-items: center; gap: 8px; white-space: nowrap;
}
.header .controls { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.file-upload { display: flex; align-items: center; gap: 5px; }

/* Split Panes Layout */
.split { display: flex; width: 100%; height: 100%; }
.gutter { background-color: var(--gutter-color); cursor: col-resize; }
.gutter.gutter-horizontal {
    background-image: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAeCAYAAADkftS9AAAAIklEQVQoU2M4c+bMfxAGAgYYmwGrIIiDjrELjpo5aiZeAAPRUQBx75t7AAAAAElFTkSuQmCC');
    width: 10px;
}
.panel {
    background-color: var(--panel-bg); border: 1px solid var(--border-color);
    display: flex; flex-direction: column; overflow: hidden; height: 100%;
}
.panel-content { padding: 15px; flex-grow: 1; overflow-y: auto; }
.panel-content.no-padding { padding: 0; }

/* Ace Editor */
#editor { width: 100%; height: 100%; border: none; }

/* PDF Preview */
#pdf-container { width: 100%; height: 100%; display: flex; flex-direction: column; background-color: var(--bg-color); position: relative; overflow: hidden; }
#pdf-embed-wrapper { flex-grow: 1; position: relative; overflow: hidden; }
#pdf-container embed { width: 100%; height: 100%; border: none; }
#pdf-controls { position: absolute; top: 5px; right: 5px; z-index: 10; }
#pdf-controls button, #pdf-controls a button {
    background-color: rgba(40, 44, 52, 0.7); color: var(--text-color-light); border: 1px solid var(--border-color);
    padding: 5px 8px; font-size: 12px; cursor: pointer; border-radius: 3px; margin-left: 5px; transition: background-color 0.2s ease;
}
#pdf-controls button:hover, #pdf-controls a button:hover { background-color: rgba(40, 44, 52, 0.9); }
#pdf-controls a { text-decoration: none; }

/* Console/Log/AI Output */
pre#console, pre#ai-output {
    white-space: pre-wrap; word-wrap: break-word; background-color: var(--input-bg); padding: 10px;
    border: none; border-radius: 4px; color: var(--text-color); font-family: var(--font-mono);
    font-size: 0.9em; flex-grow: 1; overflow-y: auto; height: 100%;
}
#console div { margin-bottom: 3px; line-height: 1.4; }

/* File List */
.file-list { list-style: none; padding: 0; margin: 0; }
.file-item { display: flex; justify-content: space-between; align-items: center; padding: 8px 12px; border-bottom: 1px solid var(--border-color); cursor: pointer; transition: background-color 0.2s ease; user-select: none; }
.file-item:last-child { border-bottom: none; }
.file-item:hover { background-color: var(--button-bg); }
.file-item.active { background-color: var(--accent-color); color: var(--bg-color); font-weight: bold; }
.file-item.active .file-actions button { color: var(--bg-color); }
.file-name { flex-grow: 1; margin-right: 10px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.file-actions button { background: none; border: none; color: var(--text-color-light); cursor: pointer; padding: 2px 4px; font-size: 0.9em; transition: color 0.2s ease; }
.file-actions button:hover { color: var(--accent-color); }
.file-actions button.delete:hover { color: var(--error-color); }

/* Buttons, Inputs, Labels */
button, input[type="file"]::-webkit-file-upload-button, label.button {
    padding: 8px 16px; background-color: var(--button-bg); color: var(--text-color-light);
    border: none; border-radius: 4px; cursor: pointer; font-size: 0.9em;
    transition: background-color 0.2s ease, color 0.2s ease, opacity 0.2s ease;
    display: inline-flex; align-items: center; gap: 8px; white-space: nowrap; vertical-align: middle;
}
button:hover, label.button:hover { background-color: var(--button-hover-bg); }
button:disabled { background-color: #cccccc30 !important; color: #aaaaaa80 !important; cursor: not-allowed; opacity: 0.6; }
button .fa-spin { /* margin-right: 5px; - Handled by gap */ }
button.primary { background-color: var(--accent-color); color: white; }
button.primary:hover { background-color: var(--accent-color-hover); }
button.success { background-color: var(--success-color); color: white; }
button.success:hover { background-color: var(--success-color-hover); }
button.danger { background-color: var(--error-color); color: white; }
button.danger:hover { background-color: var(--error-color-hover); }
/* Use label styled as button for file input */
input[type="file"] { display: none; }
label.button { margin: 0; /* Reset margin if needed */ }

input[type="text"], input[type="url"], input[type="password"], textarea {
    padding: 8px 10px; background-color: var(--input-bg); border: 1px solid var(--border-color);
    border-radius: 4px; color: var(--text-color); font-size: 0.9em; width: 100%; font-family: inherit;
}
textarea { min-height: 80px; font-family: var(--font-mono); line-height: 1.4; }
label { display: block; margin-bottom: 5px; font-weight: 600; font-size: 0.9em; }
.form-group { margin-bottom: 15px; }
.form-group small { font-size: 0.85em; color: var(--tab-text); display: block; margin-top: 3px; line-height: 1.3; }
hr { border: none; border-top: 1px solid var(--border-color); margin: 20px 0; }

/* Tabs */
.tabs { display: flex; border-bottom: 1px solid var(--border-color); background-color: var(--bg-color); flex-shrink: 0; }
.tab { padding: 10px 15px; background-color: var(--tab-bg); color: var(--tab-text); border: none; border-bottom: 3px solid transparent; cursor: pointer; font-size: 0.9em; transition: all 0.2s ease; margin-bottom: -1px; display: inline-flex; align-items: center; gap: 8px; }
.tab:hover { background-color: var(--tab-active-bg); color: var(--tab-active-text); }
.tab.active { background-color: var(--panel-bg); color: var(--text-color-light); border-bottom: 3px solid var(--accent-color); font-weight: 600; }
.tab-content { flex-grow: 1; overflow-y: auto; }
.tab-content > div:not(.active) { display: none; }