/* ============================================================
   XARXES INFORMÀTIQUES — Plataforma Educativa
   Estils principals (styles.css)
   2n Batxillerat LOMLOE — Programació, Sistemes i Xarxes II
   ============================================================ */

/* ---------- Variables CSS globals — valors no-color (sempre actius) ---------- */
:root {
  --font-mono:   'Courier New', Courier, monospace;
  --font-sans:   'Segoe UI', system-ui, sans-serif;
  --radius:      8px;
  --radius-lg:   12px;
  --transition:  0.2s ease;
}

/* ── Tema: FOSC (per defecte) ─────────────────────────────── */
[data-theme="dark"] {
  --color-primary:   #1a73e8;
  --color-secondary: #0d47a1;
  --color-accent:    #00bcd4;
  --color-success:   #43a047;
  --color-warning:   #fb8c00;
  --color-danger:    #e53935;
  --color-bg:        #0a0e1a;
  --color-bg2:       #111827;
  --color-card:      #1e2736;
  --color-border:    #2d3748;
  --color-text:      #e2e8f0;
  --color-text-muted:#94a3b8;
  --color-terminal:  #0d1117;
  --color-green:     #00ff41;
  --shadow:          0 4px 20px rgba(0,0,0,0.4);
}

/* ── Tema: CLAR ───────────────────────────────────────────── */
[data-theme="light"] {
  --color-primary:   #1565c0;
  --color-secondary: #0d47a1;
  --color-accent:    #0097a7;
  --color-success:   #2e7d32;
  --color-warning:   #e65100;
  --color-danger:    #c62828;
  --color-bg:        #f0f4f8;
  --color-bg2:       #e2e8f0;
  --color-card:      #ffffff;
  --color-border:    #cbd5e0;
  --color-text:      #1a202c;
  --color-text-muted:#4a5568;
  --color-terminal:  #1a202c;
  --color-green:     #276749;
  --shadow:          0 4px 20px rgba(0,0,0,0.12);
}

/* ── Tema: TERMINAL ───────────────────────────────────────── */
[data-theme="terminal"] {
  --color-primary:   #00ff41;
  --color-secondary: #00cc33;
  --color-accent:    #00e5ff;
  --color-success:   #00ff41;
  --color-warning:   #ffff00;
  --color-danger:    #ff3333;
  --color-bg:        #000000;
  --color-bg2:       #0a0a0a;
  --color-card:      #0d0d0d;
  --color-border:    #00ff4133;
  --color-text:      #00ff41;
  --color-text-muted:#00aa2b;
  --color-terminal:  #000000;
  --color-green:     #00ff41;
  --font-mono:       'Courier New', Courier, monospace;
  --font-sans:       'Courier New', Courier, monospace;
  --shadow:          0 4px 20px rgba(0,255,65,0.15);
}

/* ── Tema: OCEÀNIC ────────────────────────────────────────── */
[data-theme="oceanic"] {
  --color-primary:   #00acc1;
  --color-secondary: #00838f;
  --color-accent:    #4dd0e1;
  --color-success:   #26a69a;
  --color-warning:   #ffa726;
  --color-danger:    #ef5350;
  --color-bg:        #0a1929;
  --color-bg2:       #0d2137;
  --color-card:      #132f4c;
  --color-border:    #1e4976;
  --color-text:      #cdd8e3;
  --color-text-muted:#7b9eb5;
  --color-terminal:  #071223;
  --color-green:     #4dd0e1;
  --shadow:          0 4px 20px rgba(0,0,0,0.5);
}

/* ── Tema: POSTA DE SOL ───────────────────────────────────── */
[data-theme="sunset"] {
  --color-primary:   #e040fb;
  --color-secondary: #aa00ff;
  --color-accent:    #ff6d00;
  --color-success:   #69f0ae;
  --color-warning:   #ffab40;
  --color-danger:    #ff5252;
  --color-bg:        #120a1e;
  --color-bg2:       #1a0e2e;
  --color-card:      #251538;
  --color-border:    #3d1f5e;
  --color-text:      #f0e6ff;
  --color-text-muted:#b39ddb;
  --color-terminal:  #0a0612;
  --color-green:     #69f0ae;
  --shadow:          0 4px 20px rgba(100,0,150,0.4);
}

/* ---------- Reset i base ---------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* ---------- Scrollbar personalitzada ---------- */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--color-bg); }
::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-primary); }

/* ---------- Header ---------- */
#main-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 60px;
  background: var(--color-bg2);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  z-index: 1000;
  box-shadow: var(--shadow);
}

#main-header .logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.5px;
}

#main-header .logo .logo-icon {
  font-size: 1.5rem;
  animation: pulse 3s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* Barra de cerca global */
#global-search-bar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 24px;
  padding: 0.4rem 1rem;
  width: 280px;
  transition: border-color var(--transition);
}

#global-search-bar:focus-within {
  border-color: var(--color-primary);
}

#global-search-bar input {
  background: none;
  border: none;
  outline: none;
  color: var(--color-text);
  font-size: 0.9rem;
  width: 100%;
  font-family: var(--font-sans);
}

#global-search-bar input::placeholder { color: var(--color-text-muted); }

/* Botons de capçalera */
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-header {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  padding: 0.4rem 0.9rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: all var(--transition);
  font-family: var(--font-sans);
}

.btn-header:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: white;
}

.btn-header.active {
  background: var(--color-warning);
  border-color: var(--color-warning);
  color: #000;
}

/* ---------- Layout principal ---------- */
#app-layout {
  display: flex;
  padding-top: 60px;
  min-height: 100vh;
}

/* ---------- Sidebar esquerra ---------- */
#sidebar {
  width: 260px;
  min-width: 260px;
  background: var(--color-bg2);
  border-right: 1px solid var(--color-border);
  height: calc(100vh - 60px);
  position: fixed;
  top: 60px;
  left: 0;
  overflow-y: auto;
  transition: transform var(--transition);
  z-index: 900;
}

#sidebar.collapsed {
  transform: translateX(-260px);
}

/* Navegació lateral */
.sidebar-nav {
  padding: 1rem 0;
}

.nav-section-title {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--color-text-muted);
  padding: 0.8rem 1.2rem 0.4rem;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.65rem 1.2rem;
  color: var(--color-text-muted);
  cursor: pointer;
  border-left: 3px solid transparent;
  transition: all var(--transition);
  font-size: 0.88rem;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: var(--font-sans);
}

.nav-item:hover {
  background: rgba(26, 115, 232, 0.1);
  color: var(--color-text);
  border-left-color: var(--color-primary);
}

.nav-item.active {
  background: rgba(26, 115, 232, 0.15);
  color: var(--color-accent);
  border-left-color: var(--color-accent);
  font-weight: 600;
}

.nav-item .nav-icon { font-size: 1.1rem; }

/* Barra de progrés al sidebar */
.sidebar-progress {
  padding: 1rem 1.2rem;
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
}

.progress-bar-container {
  background: var(--color-card);
  border-radius: 10px;
  height: 8px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  border-radius: 10px;
  transition: width 0.5s ease;
}

/* ---------- Contingut principal ---------- */
#main-content {
  flex: 1;
  margin-left: 260px;
  padding: 2rem;
  transition: margin-left var(--transition);
  min-height: calc(100vh - 60px);
}

#main-content.sidebar-collapsed {
  margin-left: 0;
}

/* ---------- Vistes (pàgines) ---------- */
.view {
  display: none;
  animation: fadeIn 0.3s ease;
}

.view.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ---------- Targetes (cards) ---------- */
.card {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow);
}

.card-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
}

.card-icon { font-size: 1.4rem; }

/* ---------- Botons generals ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.2rem;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  font-weight: 500;
  transition: all var(--transition);
  text-decoration: none;
}

.btn-primary {
  background: var(--color-primary);
  color: white;
}
.btn-primary:hover { background: #1557b0; }

.btn-success {
  background: var(--color-success);
  color: white;
}
.btn-success:hover { background: #2e7d32; }

.btn-warning {
  background: var(--color-warning);
  color: #000;
}
.btn-warning:hover { background: #e65100; color: white; }

.btn-danger {
  background: var(--color-danger);
  color: white;
}
.btn-danger:hover { background: #b71c1c; }

.btn-outline {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
}
.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-sm {
  padding: 0.3rem 0.7rem;
  font-size: 0.8rem;
}

/* ---------- Blocs de terminal ---------- */
.terminal-block {
  background: var(--color-terminal);
  border: 1px solid #30363d;
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 0.75rem 0;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  position: relative;
  overflow: hidden;
}

.terminal-block::before {
  content: '● ● ●';
  display: block;
  color: #666;
  font-size: 0.7rem;
  margin-bottom: 0.75rem;
  letter-spacing: 4px;
}

.terminal-line {
  color: var(--color-green);
  line-height: 1.8;
  white-space: pre-wrap;
  word-break: break-all;
}

.terminal-line.comment {
  color: #6a737d;
}

.terminal-line.output {
  color: #c9d1d9;
}

.terminal-prompt {
  color: var(--color-accent);
  user-select: none;
}

.terminal-copy-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.75rem;
  background: rgba(255,255,255,0.05);
  border: 1px solid #30363d;
  color: #8b949e;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.75rem;
  font-family: var(--font-sans);
  transition: all var(--transition);
}

.terminal-copy-btn:hover {
  background: rgba(255,255,255,0.12);
  color: var(--color-text);
}

.terminal-copy-btn.copied {
  color: var(--color-success);
  border-color: var(--color-success);
}

/* ---------- Badges i etiquetes ---------- */
.badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.3px;
}

.badge-primary { background: rgba(26, 115, 232, 0.2); color: #60a5fa; }
.badge-success { background: rgba(67, 160, 71, 0.2); color: #4ade80; }
.badge-warning { background: rgba(251, 140, 0, 0.2); color: #fbbf24; }
.badge-danger  { background: rgba(229, 57, 53, 0.2); color: #f87171; }
.badge-info    { background: rgba(0, 188, 212, 0.2); color: #22d3ee; }

/* ---------- Títols de secció ---------- */
.section-title {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.4rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.section-subtitle {
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

/* ---------- Grid de targetes ---------- */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }

/* ---------- Modal ---------- */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 9999;
  place-items: center;
  animation: fadeIn 0.2s ease;
}

.modal-overlay.active {
  display: grid;
}

.modal {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  max-width: 500px;
  width: 90%;
  box-shadow: var(--shadow);
  animation: slideUp 0.3s ease;
}

@keyframes slideUp {
  from { transform: translateY(20px); opacity: 0; }
  to   { transform: translateY(0); opacity: 1; }
}

.modal-title {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--color-accent);
}

/* ---------- Formularis ---------- */
.form-group {
  margin-bottom: 1rem;
}

.form-label {
  display: block;
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 0.4rem;
  font-weight: 500;
}

.form-control {
  width: 100%;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  padding: 0.6rem 0.9rem;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  outline: none;
  transition: border-color var(--transition);
}

.form-control:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.15);
}

/* ---------- Notificació toast ---------- */
#toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 99999;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.toast {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.8rem 1.2rem;
  box-shadow: var(--shadow);
  animation: slideInRight 0.3s ease;
  max-width: 300px;
  font-size: 0.9rem;
}

.toast.success { border-left: 4px solid var(--color-success); }
.toast.error   { border-left: 4px solid var(--color-danger); }
.toast.info    { border-left: 4px solid var(--color-primary); }

@keyframes slideInRight {
  from { transform: translateX(100px); opacity: 0; }
  to   { transform: translateX(0); opacity: 1; }
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  #sidebar {
    transform: translateX(-260px);
  }
  #sidebar.mobile-open {
    transform: translateX(0);
  }
  #main-content {
    margin-left: 0;
    padding: 1rem;
  }
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
  #global-search-bar {
    width: 180px;
  }
}

/* ============================================================
   MILLORES DE LAYOUT I SIDEBAR — afegit
   ============================================================ */

/* App shell layout */
.app-shell {
  display: flex;
  min-height: 100vh;
}

/* Sidebar principal — override ID styles for new layout */
#sidebar {
  width: 240px;
  min-width: 240px;
  background: var(--color-bg2);
  border-right: 1px solid var(--color-border);
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  overflow-y: auto;
  overflow-x: hidden;
  transition: transform 0.3s cubic-bezier(0.4,0,0.2,1), width 0.3s ease;
  z-index: 900;
  display: flex;
  flex-direction: column;
  scrollbar-width: thin;
  scrollbar-color: var(--color-border) transparent;
}

#sidebar.collapsed {
  transform: translateX(-240px);
}

/* Botó flotant per reobrir sidebar quan col·lapsat */
#sidebar-open-btn {
  position: fixed;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  z-index: 950;
  background: var(--color-primary);
  color: white;
  border: none;
  width: 22px;
  height: 60px;
  border-radius: 0 8px 8px 0;
  cursor: pointer;
  font-size: 0.9rem;
  display: none;
  align-items: center;
  justify-content: center;
  box-shadow: 2px 0 12px rgba(26,115,232,0.4);
  transition: width 0.2s ease, background 0.2s ease;
  writing-mode: vertical-rl;
  letter-spacing: 0.05em;
  font-family: var(--font-sans);
  font-weight: 600;
}

#sidebar-open-btn:hover {
  width: 30px;
  background: var(--color-secondary);
}

#sidebar.collapsed ~ #sidebar-open-btn,
body.sidebar-collapsed #sidebar-open-btn {
  display: flex;
}

/* Main content */
.main-content {
  flex: 1;
  margin-left: 240px;
  padding: 2rem;
  transition: margin-left 0.3s cubic-bezier(0.4,0,0.2,1);
  min-height: 100vh;
  overflow-y: auto;
}

.main-content.sidebar-collapsed {
  margin-left: 0;
}

/* Sidebar header (brand + toggle) */
.sidebar__header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 1.25rem 1rem 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.sidebar__brand {
  flex: 1;
  min-width: 0;
}

.sidebar__brand h1 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.5px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.sidebar__brand .eyebrow {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--color-text-muted);
  margin-bottom: 0.1rem;
}

.sidebar-toggle {
  background: var(--color-card);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  width: 30px;
  height: 30px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all var(--transition);
}

.sidebar-toggle:hover {
  background: var(--color-border);
  color: var(--color-text);
}

/* Search box en sidebar */
.search-box {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin: 0.75rem 0.75rem 0.25rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 0.4rem 0.75rem;
  transition: border-color 0.2s ease, background 0.2s ease;
  cursor: text;
}

.search-box:focus-within {
  border-color: var(--color-primary);
  background: rgba(26,115,232,0.06);
  box-shadow: 0 0 0 3px rgba(26,115,232,0.12);
}

.search-box::before {
  content: '🔍';
  font-size: 0.8rem;
  flex-shrink: 0;
  opacity: 0.6;
}

.search-box input {
  background: none;
  border: none;
  outline: none;
  color: var(--color-text);
  font-size: 0.82rem;
  width: 100%;
  font-family: var(--font-sans);
}

.search-box input::placeholder {
  color: var(--color-text-muted);
  font-size: 0.78rem;
}

/* Nav list */
.nav-list {
  list-style: none;
  padding: 0.5rem 0;
  flex: 1;
}

.nav-list li {
  padding: 0 0.5rem;
  margin-bottom: 2px;
}

/* Override existing .nav-item for new sidebar */
.nav-list .nav-item {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.6rem 0.75rem;
  color: var(--color-text-muted);
  cursor: pointer;
  border-left: none;
  border-radius: 8px;
  transition: all 0.18s ease;
  font-size: 0.85rem;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: var(--font-sans);
  font-weight: 500;
}

.nav-list .nav-item:hover {
  background: var(--color-card);
  color: var(--color-text);
}

.nav-list .nav-item.active {
  background: var(--color-card);
  color: var(--color-primary);
  font-weight: 600;
}

.nav-list .nav-item.active .nav-icon {
  filter: drop-shadow(0 0 4px rgba(96,165,250,0.5));
}

.nav-list .nav-item .nav-icon {
  font-size: 1rem;
  width: 20px;
  text-align: center;
  flex-shrink: 0;
}

.nav-list .nav-item .nav-label {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Nav section divider */
.nav-divider {
  height: 1px;
  background: var(--color-border);
  margin: 0.5rem 0.75rem;
}

/* Sidebar panels (progress, teacher) */
.sidebar__panel {
  padding: 1rem 0.75rem;
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.sidebar__panel:first-of-type {
  margin-top: 0;
}

.sidebar__panel-title {
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--color-text-muted);
  margin-bottom: 0.6rem;
}

/* Progress bar in sidebar */
.progress-bar {
  background: var(--color-border);
  border-radius: 10px;
  height: 6px;
  overflow: hidden;
  margin-bottom: 0.4rem;
}

.progress-bar__fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  border-radius: 10px;
  transition: width 0.6s ease;
}

/* Teacher indicator (top bar) */
.teacher-indicator {
  display: none;
  position: fixed;
  top: 0; left: 0; right: 0;
  height: 28px;
  background: linear-gradient(90deg, #b45309, #d97706);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  text-align: center;
  line-height: 28px;
  z-index: 9999;
  letter-spacing: 0.5px;
}

.teacher-indicator.visible {
  display: block;
}

/* Modal fixes */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.7);
  z-index: 9999;
  display: none;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-overlay {
  position: absolute;
  inset: 0;
}

.modal-box {
  position: relative;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  max-width: 440px;
  width: 90%;
  box-shadow: 0 25px 50px rgba(0,0,0,0.5);
  z-index: 1;
}

/* Button system (BEM style — .button.button--*) */
.button {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.5rem 1rem;
  border-radius: 7px;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  font-family: var(--font-sans);
  font-weight: 500;
  transition: all 0.18s ease;
  white-space: nowrap;
}

.button--primary {
  background: var(--color-primary);
  color: white;
}
.button--primary:hover { background: #1557b0; transform: translateY(-1px); }
.button--primary:active { transform: translateY(0); }

.button--secondary {
  background: rgba(26,115,232,0.12);
  color: #60a5fa;
  border: 1px solid rgba(26,115,232,0.25);
}
.button--secondary:hover { background: rgba(26,115,232,0.2); }

.button--ghost {
  background: var(--color-card);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
}
.button--ghost:hover { background: var(--color-border); color: var(--color-text); }
.button--ghost.active { background: rgba(251,140,0,0.15); color: var(--color-warning); border-color: rgba(251,140,0,0.3); }

.button--sm {
  padding: 0.3rem 0.65rem;
  font-size: 0.78rem;
}

/* Hero section */
.hero {
  background: linear-gradient(135deg, rgba(26,115,232,0.08) 0%, rgba(0,188,212,0.05) 100%);
  border: 1px solid rgba(26,115,232,0.15);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 1.5rem;
}

.hero .eyebrow {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--color-accent);
  margin-bottom: 0.5rem;
}

.hero h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.75rem;
  line-height: 1.3;
}

/* Topic grid (home) */
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

/* Section heading */
.section-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.section-heading h2, .section-heading h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: 0.5rem 1rem;
  z-index: 9999;
  text-decoration: none;
}
.skip-link:focus { top: 0; }

/* SR-only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}

/* Table styles */
.table-responsive { overflow-x: auto; }
.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}
.data-table th {
  text-align: left;
  padding: 0.6rem 0.75rem;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--color-text-muted);
  border-bottom: 2px solid var(--color-border);
}
.data-table td {
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid rgba(45,55,72,0.5);
  vertical-align: middle;
}
.data-table tr:hover td { background: rgba(255,255,255,0.025); }

/* Port number badge */
.port-number {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-accent);
  font-weight: 600;
}

/* Terminal output (simulators) */
.terminal-output {
  background: var(--color-terminal);
  border: 1px solid #30363d;
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.8;
  min-height: 80px;
}

/* Sim card */
.sim-card { padding: 1.5rem; }

/* Simulator controls */
.sim-controls { margin-bottom: 1rem; }

/* Explanation box */
.explanation-box {
  background: rgba(26,115,232,0.06);
  border: 1px solid rgba(26,115,232,0.2);
  border-radius: var(--radius);
  padding: 0.85rem 1rem;
  font-size: 0.86rem;
  line-height: 1.6;
  color: var(--color-text);
}

/* Journey flow */
.journey-flow {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.journey-node {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1rem;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: all 0.3s ease;
}

.journey-node.active {
  border-color: var(--color-warning);
  background: rgba(251,140,0,0.08);
  box-shadow: 0 0 12px rgba(251,140,0,0.15);
}

.journey-node.completed {
  border-color: var(--color-success);
  background: rgba(67,160,71,0.06);
}

.journey-node-icon { font-size: 1.5rem; }
.journey-node-title { font-weight: 600; font-size: 0.88rem; }
.journey-node-desc { font-size: 0.76rem; color: var(--color-text-muted); }
.journey-node-status { margin-left: auto; font-size: 1.1rem; }

.journey-connector {
  width: 2px;
  height: 20px;
  background: var(--color-border);
  margin-left: 1.95rem;
  transition: background 0.3s ease;
}
.journey-connector.active { background: var(--color-warning); }

/* DNS flow */
.dns-flow {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  padding: 1rem;
  background: rgba(255,255,255,0.02);
  border-radius: var(--radius);
  border: 1px solid var(--color-border);
}

/* Packet tracer container */
.packet-tracer-container .packet-ball {
  position: absolute;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-warning);
  box-shadow: 0 0 10px var(--color-warning);
  pointer-events: none;
  z-index: 20;
}

.packet-tracer-device {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
  cursor: default;
  user-select: none;
}

.packet-tracer-device .device-icon {
  width: 48px;
  height: 48px;
  background: var(--color-card);
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  transition: border-color 0.3s, box-shadow 0.3s;
}

.packet-tracer-device.highlighted .device-icon {
  border-color: var(--color-warning);
  box-shadow: 0 0 14px rgba(251,140,0,0.4);
}

.device-label { font-size: 0.72rem; font-weight: 600; color: var(--color-text-muted); }

/* Binary display */
.binary-display {
  background: var(--color-terminal);
  border: 1px solid #30363d;
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  font-family: var(--font-mono);
}

.binary-network { color: #f87171; font-weight: 600; }
.binary-host { color: #4ade80; font-weight: 600; }

/* Ping lines */
.ping-line { color: var(--color-green); line-height: 1.7; }
.ping-line.info { color: #60a5fa; }
.ping-line.output { color: #c9d1d9; }
.ping-line.success { color: #4ade80; }
.ping-line.error { color: #f87171; }
.ping-line.summary { color: var(--color-warning); }

/* Exercise list */
.exercise-list { display: flex; flex-direction: column; gap: 1rem; }

.exercise-card {
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: border-color 0.2s;
}
.exercise-card.correct { border-left: 4px solid var(--color-success); }
.exercise-card.incorrect { border-left: 4px solid var(--color-danger); }

.exercise-header { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 0.75rem; }
.exercise-meta { display: flex; gap: 0.4rem; flex-wrap: wrap; }
.exercise-points { font-size: 0.82rem; color: var(--color-warning); font-weight: 600; }
.exercise-question { font-weight: 600; margin-bottom: 1rem; line-height: 1.5; }

.exercise-options { display: flex; flex-direction: column; gap: 0.5rem; margin-bottom: 0.75rem; }

.option-btn {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.9rem;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  color: var(--color-text);
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 0.88rem;
  text-align: left;
  transition: all 0.15s ease;
}
.option-btn:hover:not(:disabled) { border-color: var(--color-primary); background: rgba(26,115,232,0.08); }
.option-btn.correct { border-color: var(--color-success); background: rgba(67,160,71,0.12); color: #4ade80; }
.option-btn.incorrect { border-color: var(--color-danger); background: rgba(229,57,53,0.12); color: #f87171; }
.option-btn:disabled { cursor: default; }

.option-letter {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: rgba(255,255,255,0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.72rem;
  font-weight: 700;
  flex-shrink: 0;
}

.exercise-explanation {
  display: none;
  padding: 0.75rem;
  border-radius: 6px;
  font-size: 0.85rem;
  margin-top: 0.75rem;
  line-height: 1.5;
}
.exercise-explanation.show.correct { display: block; background: rgba(67,160,71,0.1); border: 1px solid rgba(67,160,71,0.3); color: #4ade80; }
.exercise-explanation.show.incorrect { display: block; background: rgba(229,57,53,0.1); border: 1px solid rgba(229,57,53,0.3); color: #f87171; }

/* Stat cards */
.stat-card {
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem;
  text-align: center;
}
.stat-card__label { font-size: 0.75rem; color: var(--color-text-muted); margin-bottom: 0.4rem; text-transform: uppercase; letter-spacing: 0.5px; }
.stat-card strong { font-size: 1.5rem; color: var(--color-accent); }

/* Section title (simulators page) */
.section-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 1.25rem;
  color: var(--color-text);
}

/* Device library (editor) */
.device-library {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

/* Editor panel */
.editor-panel {
  background: var(--color-bg2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.75rem;
  overflow-y: auto;
}

/* Toast container */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 99999;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* ============================================================
   OVERRIDES PER TEMES — elements amb colors hardcoded
   ============================================================ */

/* Tema CLAR: header, sidebar, canvas i terminal */
[data-theme="light"] body {
  background-color: var(--color-bg);
  color: var(--color-text);
}
[data-theme="light"] #main-header {
  background: linear-gradient(135deg, #dde6f0, #c8d8eb);
  border-bottom-color: #a0b8d0;
}
[data-theme="light"] #main-header .logo { color: var(--color-primary); }
[data-theme="light"] .sidebar {
  background: #ffffff;
  border-right-color: var(--color-border);
}
[data-theme="light"] .sidebar__header { background: #f7fafc; border-bottom-color: var(--color-border); }
[data-theme="light"] .nav-item:hover  { background: rgba(21,101,192,0.08); }
[data-theme="light"] .nav-item.active { background: rgba(21,101,192,0.13); }
[data-theme="light"] .packet-log      { background: #1a202c; color: #a0f0a0; }
[data-theme="light"] .editor-canvas-container {
  background-image: radial-gradient(circle, rgba(100,130,160,0.35) 1px, transparent 1px);
}
[data-theme="light"] .canvas-statusbar {
  background: rgba(220,230,240,0.92);
  border-top-color: rgba(0,0,0,0.1);
  color: #4a5568;
}
[data-theme="light"] .canvas-statusbar-item span { color: var(--color-primary); }
[data-theme="light"] .properties-panel {
  background: rgba(255,255,255,0.97);
  border-color: var(--color-primary);
  box-shadow: 0 8px 32px rgba(0,0,0,0.15);
  color: var(--color-text);
}
[data-theme="light"] .canvas-device-icon { background: #ffffff; border-color: #a0b8d0; }
[data-theme="light"] .canvas-device-label { color: #4a5568; }
[data-theme="light"] .canvas-device-ip   { color: var(--color-primary); }

/* Tema TERMINAL: tot en verd fosc/negre */
[data-theme="terminal"] .minimap-hint         { color: #00aa2b; }
[data-theme="terminal"] body { font-family: var(--font-mono); }
[data-theme="terminal"] #main-header {
  background: #000000;
  border-bottom: 1px solid #00ff4144;
}
[data-theme="terminal"] .sidebar { background: #000000; border-right-color: #00ff4133; }
[data-theme="terminal"] .sidebar__header { background: #050505; border-bottom-color: #00ff4133; }
[data-theme="terminal"] .nav-item { color: #00aa2b; }
[data-theme="terminal"] .nav-item:hover { background: rgba(0,255,65,0.07); color: #00ff41; border-left-color: #00ff41; }
[data-theme="terminal"] .nav-item.active { background: rgba(0,255,65,0.12); color: #00ff41; border-left-color: #00ff41; }
[data-theme="terminal"] .card { border-color: #00ff4133; }
[data-theme="terminal"] .editor-canvas-container {
  background-image: radial-gradient(circle, rgba(0,255,65,0.18) 1px, transparent 1px);
  background-color: #000;
}
[data-theme="terminal"] .canvas-statusbar {
  background: rgba(0,10,0,0.9);
  border-top-color: #00ff4133;
  color: #00aa2b;
}
[data-theme="terminal"] .canvas-statusbar-item span { color: #00ff41; }
[data-theme="terminal"] .properties-panel {
  background: rgba(0,8,0,0.97);
  border-color: #00ff41;
  box-shadow: 0 0 20px rgba(0,255,65,0.2);
}
[data-theme="terminal"] .canvas-device-icon { background: #0a0a0a; border-color: #00ff4155; }
[data-theme="terminal"] .editor-tool-btn:hover { background: #00ff41; color: #000; }
[data-theme="terminal"] .hero { border-color: #00ff4133; }

/* Tema OCEÀNIC */
[data-theme="oceanic"] #main-header {
  background: linear-gradient(135deg, #0d2137, #071e33);
  border-bottom-color: #1e4976;
}
[data-theme="oceanic"] .canvas-statusbar {
  background: rgba(7,18,35,0.85);
  border-top-color: #1e4976;
}
[data-theme="oceanic"] .editor-canvas-container {
  background-image: radial-gradient(circle, rgba(0,172,193,0.2) 1px, transparent 1px);
}
[data-theme="oceanic"] .properties-panel {
  background: rgba(13,33,55,0.96);
  border-color: var(--color-primary);
  box-shadow: 0 8px 32px rgba(0,0,0,0.6), 0 0 0 1px rgba(0,172,193,0.3);
}

/* Tema POSTA DE SOL */
[data-theme="sunset"] #main-header {
  background: linear-gradient(135deg, #1a0e2e, #0e0818);
  border-bottom-color: #3d1f5e;
}
[data-theme="sunset"] .canvas-statusbar {
  background: rgba(18,10,30,0.88);
  border-top-color: #3d1f5e;
}
[data-theme="sunset"] .editor-canvas-container {
  background-image: radial-gradient(circle, rgba(224,64,251,0.15) 1px, transparent 1px);
}
[data-theme="sunset"] .properties-panel {
  background: rgba(26,14,46,0.96);
  border-color: var(--color-primary);
  box-shadow: 0 8px 32px rgba(100,0,150,0.4), 0 0 0 1px rgba(224,64,251,0.3);
}
[data-theme="sunset"] .nav-item:hover  { background: rgba(224,64,251,0.1); border-left-color: var(--color-primary); }
[data-theme="sunset"] .nav-item.active { background: rgba(224,64,251,0.15); border-left-color: var(--color-accent); color: var(--color-accent); }

/* ── Selector de tema (widget al sidebar) ───────────────────── */
.theme-picker {
  padding: 0.85rem 1.2rem;
  border-top: 1px solid var(--color-border);
}

.theme-picker__label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--color-text-muted);
  margin-bottom: 0.55rem;
  display: block;
}

.theme-picker__grid {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.theme-btn {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, border-color 0.15s ease;
  position: relative;
  flex-shrink: 0;
}

.theme-btn:hover { transform: scale(1.18); }

.theme-btn.active {
  border-color: var(--color-text);
  transform: scale(1.12);
}

.theme-btn[data-theme-id="dark"]     { background: linear-gradient(135deg, #0a0e1a 50%, #1a73e8 50%); }
.theme-btn[data-theme-id="light"]    { background: linear-gradient(135deg, #f0f4f8 50%, #1565c0 50%); }
.theme-btn[data-theme-id="terminal"] { background: linear-gradient(135deg, #000000 50%, #00ff41 50%); }
.theme-btn[data-theme-id="oceanic"]  { background: linear-gradient(135deg, #0a1929 50%, #00acc1 50%); }
.theme-btn[data-theme-id="sunset"]   { background: linear-gradient(135deg, #120a1e 50%, #e040fb 50%); }

.theme-btn[title]::after {
  content: attr(title);
  position: absolute;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 2px 7px;
  font-size: 0.65rem;
  white-space: nowrap;
  color: var(--color-text);
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  z-index: 1000;
}

.theme-btn:hover::after { opacity: 1; }