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

html,
body {
  height: 100%;
  width: 100%;
}

:root{
  /* Colours */
  --primary-bg-color: #1e1e1e;
  --sidebar-bg-color: #181818;
  --bg-grey-color: #2a2a2a;
  --text-color: #e5e5e5;
  --button-bg-color: #1d7bda;
  --button-bg-color-hover: #0b355f;
  --tumbnail-dark-bg-color: #111;

  /* Padding */
  --padding-s:6px;
  --padding-m:10px;
  --padding-l:20px;
  --padding-xl:30px;
  --padding-2xl:40px;

  /* Border Radius */
  --border-radius-s: 4px;
  --border-radius-m: 6px;
  --border-radius-l: 12px;

  /* Responsive Sizes */
  --sidebar-width: 240px;
}

body {
  background: var(--primary-bg-color);
  color: var(--text-color);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

/* Loading Screen */
.loading-screen {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--primary-bg-color);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 1;
  transition: opacity 0.5s ease;
}

.loading-screen.hide {
  opacity: 0;
  pointer-events: none;
}

.loading-icon {
  font-size: 80px;
  color: var(--button-bg-color);
  animation: pulse 1.5s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.2);
    opacity: 0.7;
  }
}

.app {
  display: flex;
  height: 100vh;
  position: relative;
  opacity: 0;
  transition: opacity 0.5s ease;
}

.app.show {
  opacity: 1;
}

/* Sidebar */
.sidebar {
  background: var(--sidebar-bg-color);
  padding: var(--padding-l);
  display: flex;
  flex-direction: column;
  gap: var(--padding-l);
  width: var(--sidebar-width);
  flex-shrink: 0;
  transition: transform 0.3s ease;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--padding-m);
}

.logo img {
  max-width: 32px;
  height: auto;
}

.logo span {
  font-size: 1.5rem;
  font-weight: bold;
}

.search {
  padding: var(--padding-m);
  border-radius: var(--border-radius-m);
  border: none;
  background: var(--bg-grey-color);
  color: var(--text-color);
  font-size: 14px;
}

.search::placeholder {
  color: #888;
}

.search:focus {
  outline: 2px solid var(--button-bg-color);
}

.nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.nav a {
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: var(--padding-m);
  padding: var(--padding-m);
  border-radius: var(--border-radius-m);
  color: var(--text-color);
  cursor: pointer;
  transition: all 0.3s ease;
}

.nav a i {
  font-size: 1.2rem;
  width: 20px;
  flex-shrink: 0;
}

.nav a.active,
.nav a:hover {
  background: var(--bg-grey-color);
  color: var(--text-color);
  transform: scale(1.05);
}

/* Main */
.main {
  flex: 1;
  padding: var(--padding-m);
  overflow-y: auto;
  min-width: 0;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--padding-m);
  flex-wrap: wrap;
  gap: var(--padding-m);
}

.topbar h1 {
  font-size: 1.8rem;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: var(--padding-s);
  padding: var(--padding-m) var(--padding-l);
  background-color: var(--button-bg-color);
  color: var(--text-color);
  border: none;
  border-radius: var(--border-radius-l);
  transition: all 0.3s ease;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
}

.top-actions:hover {
  background-color: var(--button-bg-color-hover);
  color: var(--text-color);
}

.top-actions:active {
  transform: scale(0.92);
}

.filters {
  padding: var(--padding-l) 0;
  display: flex;
  gap: var(--padding-m);
  flex-wrap: wrap;
}

.filters button {
  background: var(--bg-grey-color);
  color: var(--text-color);
  border: none;
  padding: var(--padding-s) var(--padding-m);
  border-radius: var(--border-radius-m);
  cursor: pointer;
  transition: all 0.2s ease;
}

.filters button:hover {
  background: #3a3a3a;
}

.filters button:active {
  transform: scale(0.95);
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--padding-l);
}

.card {
  background: var(--bg-grey-color);
  border-radius: var(--border-radius-l);
  overflow: hidden;
  cursor: pointer;
  transition: all 0.3s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.thumbnail {
  height: 150px;
  background: var(--bg-grey-color);
  display: flex;
  align-items: center;
  justify-content: center;
}

.thumbnail.dark {
  background: var(--tumbnail-dark-bg-color);
}

.thumbnail.new-project {
  background: var(--sidebar-bg-color);
  border: 2px dashed var(--bg-grey-color);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
}

.card:hover .thumbnail.new-project {
  border-color: var(--button-bg-color);
}

.thumbnail.new-project i {
  font-size: 60px;
  color: var(--text-color);
  opacity: 0.5;
  transition: all 0.3s ease;
}

.card:hover .thumbnail.new-project i {
  opacity: 1;
  color: var(--button-bg-color);
  transform: scale(1.1);
}

.card-info {
  padding: var(--padding-m);
}

.card-info h4 {
  margin-bottom: 6px;
  font-size: 1rem;
}

.card-info p {
  font-size: 0.85rem;
  color: #999;
}

/* Mobile Menu Toggle Button (Hidden by default) */
.menu-toggle {
  display: none;
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 1001;
  background: var(--sidebar-bg-color);
  border: 1px solid var(--bg-grey-color);
  color: var(--text-color);
  width: 40px;
  height: 40px;
  border-radius: var(--border-radius-m);
  cursor: pointer;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  transition: all 0.3s ease;
}

.menu-toggle:hover {
  background: var(--bg-grey-color);
}

.menu-toggle:active {
  transform: scale(0.9);
}

/* Overlay for mobile sidebar */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 999;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.sidebar-overlay.active {
  opacity: 1;
}

/* ============================================
   RESPONSIVE DESIGN - MEDIA QUERIES
   ============================================ */

/* Tablet - 1024px and below */
@media screen and (max-width: 1024px) {
  :root {
    --sidebar-width: 220px;
    --padding-l: 16px;
  }

  .logo span {
    font-size: 1.3rem;
  }

  .cards {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  }

  .topbar h1 {
    font-size: 1.6rem;
  }

  .loading-icon {
    font-size: 70px;
  }
}

/* Tablet Portrait - 768px and below */
@media screen and (max-width: 768px) {
  :root {
    --sidebar-width: 260px;
    --padding-l: 14px;
    --padding-m: 8px;
  }

  /* Show mobile menu toggle */
  .menu-toggle {
    display: flex;
  }

  /* Hide sidebar by default on mobile */
  .sidebar {
    position: fixed;
    top: 0;
    left: 0;
    bottom: 0;
    z-index: 1000;
    transform: translateX(-100%);
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.3);
  }

  /* Show sidebar when active */
  .sidebar.active {
    transform: translateX(0);
  }

  /* Show overlay when sidebar is active */
  .sidebar.active ~ .sidebar-overlay {
    display: block;
  }

  /* Adjust main content */
  .main {
    width: 100%;
    padding: var(--padding-m);
  }

  .topbar {
    padding-left: 60px;
  }

  .cards {
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: var(--padding-m);
  }

  .thumbnail {
    height: 140px;
  }

  .loading-icon {
    font-size: 60px;
  }
}

/* Mobile - 480px and below */
@media screen and (max-width: 480px) {
  :root {
    --sidebar-width: 280px;
    --padding-l: 12px;
    --padding-m: 8px;
    --padding-s: 4px;
  }

  .sidebar {
    max-width: 280px;
    padding: var(--padding-m);
  }

  .logo {
    gap: 8px;
  }

  .logo img {
    max-width: 28px;
  }

  .logo span {
    font-size: 1.2rem;
  }

  .search {
    padding: 10px;
    font-size: 13px;
  }

  .nav a {
    padding: 10px;
    font-size: 14px;
  }

  .nav a i {
    font-size: 1.1rem;
  }

  .main {
    padding: var(--padding-s);
  }

  .topbar {
    flex-direction: column;
    align-items: flex-start;
    padding: var(--padding-m);
    padding-left: 60px;
    gap: var(--padding-m);
  }

  .topbar h1 {
    font-size: 1.4rem;
  }

  .top-actions {
    width: 100%;
    justify-content: center;
    padding: 12px;
  }

  .filters {
    padding: var(--padding-m) 0;
    gap: var(--padding-s);
  }

  .filters button {
    padding: 8px 12px;
    font-size: 13px;
  }

  /* Single column cards on mobile */
  .cards {
    grid-template-columns: 1fr;
    gap: var(--padding-m);
  }

  .card-info {
    padding: 12px;
  }

  .card-info h4 {
    font-size: 0.95rem;
  }

  .card-info p {
    font-size: 0.8rem;
  }

  .thumbnail {
    height: 160px;
  }

  .thumbnail.new-project i {
    font-size: 50px;
  }

  .loading-icon {
    font-size: 50px;
  }
}

/* Very Small Mobile - 360px and below */
@media screen and (max-width: 360px) {
  .sidebar {
    max-width: 100%;
    width: 100%;
  }

  .logo span {
    font-size: 1.1rem;
  }

  .topbar h1 {
    font-size: 1.2rem;
  }

  .menu-toggle {
    width: 36px;
    height: 36px;
    font-size: 1.3rem;
    top: 16px;
    left: 16px;
  }

  .nav a {
    padding: 8px;
    font-size: 13px;
  }

  .thumbnail {
    height: 140px;
  }

  .thumbnail.new-project i {
    font-size: 45px;
  }

  .loading-icon {
    font-size: 45px;
  }
}

/* Landscape Mobile */
@media screen and (max-height: 500px) and (orientation: landscape) {
  .sidebar {
    width: 200px;
    max-width: 200px;
    padding: var(--padding-m);
    gap: var(--padding-m);
  }

  .logo {
    gap: 6px;
  }

  .logo img {
    max-width: 24px;
  }

  .logo span {
    font-size: 1rem;
  }

  .nav a {
    padding: 6px 8px;
    font-size: 13px;
  }

  .search {
    padding: 8px;
  }

  .topbar h1 {
    font-size: 1.3rem;
  }

  .loading-icon {
    font-size: 50px;
  }
}

/* Touch Device Optimizations */
@media (hover: none) and (pointer: coarse) {
  .nav a,
  .filters button,
  .top-actions,
  .card {
    min-height: 44px;
  }

  .menu-toggle {
    min-width: 44px;
    min-height: 44px;
  }

  .search {
    min-height: 44px;
  }
}

/* Scrollbar Styling */
.main::-webkit-scrollbar,
.sidebar::-webkit-scrollbar {
  width: 8px;
}

.main::-webkit-scrollbar-track,
.sidebar::-webkit-scrollbar-track {
  background: var(--sidebar-bg-color);
}

.main::-webkit-scrollbar-thumb,
.sidebar::-webkit-scrollbar-thumb {
  background: var(--bg-grey-color);
  border-radius: 4px;
}

.main::-webkit-scrollbar-thumb:hover,
.sidebar::-webkit-scrollbar-thumb:hover {
  background: #3a3a3a;
}

/* Print Styles */
@media print {
  .sidebar,
  .menu-toggle,
  .sidebar-overlay,
  .topbar,
  .filters,
  .loading-screen {
    display: none;
  }

  .main {
    padding: 0;
  }

  .cards {
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
  }
}