@import url('https://fonts.cdnfonts.com/css/sf-pro-display-style');

:root {
  --bg-primary: #FFFFFF;
  --bg-secondary: #F7F7F7;
  --bg-panel: #FAFAFA;
  --text-primary: #000000;
  --text-secondary: #222222;
  --text-muted: #555555;
  --border-color: #E0E0E0;
  --border-light: #F0F0F0;
  --accent: #000000;
  --accent-hover: #333333;
  --card-bg: #FFFFFF;
  --card-shadow: 0 1px 4px rgba(0, 0, 0, 0.06);
  --card-shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.10);
  --overlay-bg: rgba(0, 0, 0, 0.4);
  --input-bg: #FFFFFF;
  --scrollbar-thumb: #CCCCCC;
  --scrollbar-track: transparent;
  --fab-bg: #000000;
  --fab-color: #FFFFFF;
  --badge-bg: #000000;
  --badge-color: #FFFFFF;
  --toggle-bg: #CCCCCC;
  --toggle-active-bg: #000000;
  --toggle-knob: #FFFFFF;
  --search-highlight: rgba(0,0,0,0.06);
  --empty-state-color: #777777;

  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  --font-family: 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-base: 15px;
  --font-size-md: 18px;
  --font-size-lg: 22px;
  --font-size-xl: 28px;
  --font-size-2xl: 36px;
  --font-size-3xl: 48px;

  --panel-width: 260px;
  --panel-width-collapsed: 0px;
  --header-height: 60px;
  --border-radius-sm: 6px;
  --border-radius-md: 10px;
  --border-radius-lg: 16px;
  --border-radius-full: 50%;

  --transition-fast: 0.15s ease;
  --transition-base: 0.3s ease;
  --transition-slow: 0.5s ease;
}

[data-theme="dark"] {
  --bg-primary: #0A0A0A;
  --bg-secondary: #111111;
  --bg-panel: #0F0F0F;
  --text-primary: #FFFFFF;
  --text-secondary: #D0D0D0;
  --text-muted: #999999;
  --border-color: #2A2A2A;
  --border-light: #1A1A1A;
  --accent: #FFFFFF;
  --accent-hover: #CCCCCC;
  --card-bg: #141414;
  --card-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);
  --card-shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.5);
  --overlay-bg: rgba(0, 0, 0, 0.7);
  --input-bg: #1A1A1A;
  --scrollbar-thumb: #333333;
  --scrollbar-track: transparent;
  --fab-bg: #FFFFFF;
  --fab-color: #000000;
  --badge-bg: #FFFFFF;
  --badge-color: #000000;
  --toggle-bg: #333333;
  --toggle-active-bg: #FFFFFF;
  --toggle-knob: #000000;
  --search-highlight: rgba(255,255,255,0.06);
  --empty-state-color: #888888;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg-primary: #0A0A0A;
    --bg-secondary: #111111;
    --bg-panel: #0F0F0F;
    --text-primary: #FFFFFF;
    --text-secondary: #D0D0D0;
    --text-muted: #999999;
    --border-color: #2A2A2A;
    --border-light: #1A1A1A;
    --accent: #FFFFFF;
    --accent-hover: #CCCCCC;
    --card-bg: #141414;
    --card-shadow: 0 1px 4px rgba(0, 0, 0, 0.3);
    --card-shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.5);
    --overlay-bg: rgba(0, 0, 0, 0.7);
    --input-bg: #1A1A1A;
    --scrollbar-thumb: #333333;
    --scrollbar-track: transparent;
    --fab-bg: #FFFFFF;
    --fab-color: #000000;
    --badge-bg: #FFFFFF;
    --badge-color: #000000;
    --toggle-bg: #333333;
    --toggle-active-bg: #FFFFFF;
    --toggle-knob: #000000;
    --search-highlight: rgba(255,255,255,0.06);
    --empty-state-color: #888888;
  }
}

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

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-base), color var(--transition-base);
  overflow: hidden;
  height: 100vh;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  font-family: var(--font-family);
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
  font-size: inherit;
}

input, select, textarea {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  color: var(--text-primary);
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(0, 0, 0, 0.08);
}

[data-theme="dark"] input:focus,
[data-theme="dark"] select:focus,
[data-theme="dark"] textarea:focus {
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.08);
}

::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}
::-webkit-scrollbar-thumb {
  background: var(--scrollbar-thumb);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

.app {
  display: flex;
  height: 100vh;
  width: 100vw;
  overflow: hidden;
}

.side-panel {
  width: var(--panel-width);
  min-width: var(--panel-width);
  height: 100vh;
  background-color: var(--bg-panel);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  transition: transform var(--transition-base), background-color var(--transition-base), border-color var(--transition-base);
  z-index: 100;
  overflow: hidden;
}

.side-panel__header {
  padding: var(--space-xl) var(--space-lg);
  border-bottom: 1px solid var(--border-light);
}

.side-panel__logo {
  font-size: var(--font-size-xl);
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.brand-text {
  font-family: 'Gugi', sans-serif;
  letter-spacing: normal;
}

.side-panel__nav {
  flex: 1;
  padding: var(--space-lg) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  font-size: var(--font-size-md);
  color: var(--text-secondary);
  position: relative;
  transition: color var(--transition-fast), background-color var(--transition-fast);
  letter-spacing: 1px;
}

.nav-link::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%) scaleY(0);
  width: 3px;
  height: 60%;
  background-color: var(--accent);
  border-radius: 0 2px 2px 0;
  transition: transform var(--transition-fast);
}

.nav-link:hover {
  color: var(--text-primary);
  background-color: var(--search-highlight);
}

.nav-link.active {
  color: var(--text-primary);
}

.nav-link.active::before {
  transform: translateY(-50%) scaleY(1);
}

.nav-link__icon {
  width: 22px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.nav-link__icon svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.side-panel__footer {
  padding: var(--space-lg);
  border-top: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.mode-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  letter-spacing: 0.5px;
}

.mode-toggle__label {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.toggle-switch {
  width: 42px;
  height: 24px;
  background-color: var(--toggle-bg);
  border-radius: 12px;
  position: relative;
  cursor: pointer;
  transition: background-color var(--transition-fast);
  flex-shrink: 0;
}

.toggle-switch.active {
  background-color: var(--toggle-active-bg);
}

.toggle-switch__knob {
  width: 18px;
  height: 18px;
  background-color: var(--toggle-knob);
  border-radius: var(--border-radius-full);
  position: absolute;
  top: 3px;
  left: 3px;
  transition: transform var(--transition-fast), background-color var(--transition-base);
}

.toggle-switch.active .toggle-switch__knob {
  transform: translateX(18px);
}

.main-content {
  flex: 1;
  height: 100vh;
  overflow-y: auto;
  overflow-x: hidden;
  background-color: var(--bg-primary);
  transition: background-color var(--transition-base);
  position: relative;
}

.mobile-header {
  display: none;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-panel);
  position: sticky;
  top: 0;
  z-index: 90;
}

.hamburger {
  width: 36px;
  height: 36px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.hamburger__line {
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.hamburger.active .hamburger__line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.hamburger.active .hamburger__line:nth-child(2) {
  opacity: 0;
}
.hamburger.active .hamburger__line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

.mobile-header__title {
  font-size: var(--font-size-md);
  letter-spacing: 2px;
}

.page {
  display: none;
  padding: var(--space-2xl) var(--space-3xl);
  min-height: 100%;
  animation: fadeIn 0.35s ease;
}

.page.active {
  display: block;
}

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

.page__title {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: var(--space-xs);
  color: var(--text-primary);
}

.page__subtitle {
  font-size: var(--font-size-base);
  color: var(--text-secondary);
  margin-bottom: var(--space-2xl);
  letter-spacing: 1px;
}

#page-home {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  min-height: 100%;
  padding-bottom: var(--space-sm);
}

#page-home.active {
  display: flex;
}

.home-empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--empty-state-color);
}

.home-ascii-art {
  font-family: monospace;
  font-size: clamp(2.5px, 1.25vw, 9px);
  line-height: 1.2;
  white-space: pre;
  margin-bottom: var(--space-lg);
  opacity: 0.6;
  color: var(--text-primary);
  text-align: left;
  overflow-x: hidden;
  max-width: 100%;
}

.home-empty__text {
  font-size: var(--font-size-lg);
  letter-spacing: 2px;
  color: var(--empty-state-color);
}

.home-empty__subtitle {
  font-size: var(--font-size-base);
  color: var(--empty-state-color);
  font-weight: 700;
  letter-spacing: 1px;
  margin-top: var(--space-xs);
  margin-bottom: 0;
}

.home-info {
  max-width: 580px;
  margin: var(--space-md) auto 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
}

.home-mission {
  font-size: var(--font-size-base);
  color: var(--text-secondary);
  line-height: 1.6;
  letter-spacing: 0.2px;
}

.home-disclaimer {
  display: inline-flex;
  align-items: flex-start;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  line-height: 1.5;
  text-align: left;
}

.home-disclaimer__icon {
  width: 15px;
  height: 15px;
  stroke: var(--text-muted);
  stroke-width: 2;
  fill: none;
  stroke-linecap: round;
  stroke-linejoin: round;
  flex-shrink: 0;
  margin-top: 2px;
}

.home-footer {
  margin-top: auto;
  padding-top: var(--space-md);
  padding-bottom: 0;
  font-size: var(--font-size-xs);
  color: var(--text-muted);
  letter-spacing: 0.8px;
  text-align: center;
}

.home-footer__link {
  color: var(--text-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 500;
  transition: opacity var(--transition-fast);
}

.home-footer__link:hover {
  opacity: 0.75;
}

.search-bar {
  position: relative;
  margin-bottom: var(--space-xl);
}

.search-bar__input {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  padding-left: 48px;
  font-size: var(--font-size-md);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-base);
  letter-spacing: 1px;
}

.search-bar__input::placeholder {
  color: var(--text-secondary);
  letter-spacing: 1px;
}

.search-bar__input:focus {
  background-color: var(--input-bg);
  border-color: var(--accent);
}

.search-bar__icon {
  position: absolute;
  left: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  pointer-events: none;
  transition: color var(--transition-fast);
}

.search-bar__icon svg {
  width: 100%;
  height: 100%;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.search-bar__input:focus ~ .search-bar__icon,
.search-bar__input:focus + .search-bar__icon {
  color: var(--text-primary);
}

.search-bar__hint {
  position: absolute;
  right: var(--space-md);
  top: 50%;
  transform: translateY(-50%);
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  padding: 2px 8px;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius-sm);
  transition: opacity var(--transition-fast), background-color var(--transition-base);
  pointer-events: none;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: var(--space-lg);
}

.course-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  padding: var(--space-lg);
  cursor: pointer;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.course-card:hover {
  border-color: var(--accent);
  background-color: var(--search-highlight);
}

.course-card__icon {
  width: 44px;
  height: 44px;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--space-md);
  transition: background-color var(--transition-base);
}

.course-card__icon svg {
  width: 24px;
  height: 24px;
  stroke: var(--text-primary);
  fill: none;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.course-card__code {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: var(--space-xs);
}

.course-card__name {
  font-size: var(--font-size-md);
  color: var(--text-primary);
  font-weight: 600;
  letter-spacing: -0.3px;
  margin-bottom: var(--space-sm);
}

.course-card__meta {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  letter-spacing: 0.5px;
}

.course-detail {
  animation: fadeIn 0.3s ease;
}

.course-detail__header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.course-detail__back {
  width: 36px;
  height: 36px;
  border-radius: var(--border-radius-full);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.course-detail__back:hover {
  background-color: var(--search-highlight);
  border-color: var(--accent);
}

.course-detail__back svg {
  width: 18px;
  height: 18px;
  stroke: var(--text-primary);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.course-detail__info {
  flex: 1;
}

.course-detail__code {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  letter-spacing: 2px;
  text-transform: uppercase;
}

.course-detail__name {
  font-size: var(--font-size-xl);
  font-weight: 700;
  letter-spacing: -0.5px;
}

.file-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.file-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  border: 1px solid var(--border-light);
  border-radius: var(--border-radius-sm);
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.file-item:hover {
  background-color: var(--search-highlight);
  border-color: var(--border-color);
}

.file-item__icon {
  width: 40px;
  height: 40px;
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  border: 1.5px solid var(--border-color);
  color: var(--text-primary);
  transition: border-color var(--transition-base), color var(--transition-base);
}

.file-item__icon.pdf { color: var(--text-primary); }
.file-item__icon.image { color: var(--text-primary); }
.file-item__icon.video { color: var(--text-primary); }

.file-item__info {
  flex: 1;
  min-width: 0;
}

.file-item__name {
  font-size: var(--font-size-base);
  letter-spacing: 0.5px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-item__size {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
}

.file-item__download {
  width: 36px;
  height: 36px;
  border-radius: var(--border-radius-full);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
  flex-shrink: 0;
}

.file-item__download:hover {
  background-color: var(--accent);
  border-color: var(--accent);
  color: var(--bg-primary);
  transform: scale(1.08);
}

.file-item__download svg {
  width: 16px;
  height: 16px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.app-loading-screen {
  position: fixed;
  inset: 0;
  background-color: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.35s ease, visibility 0.35s ease;
}

.app-loading-screen.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.app-loading-screen .loader {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  margin: 0;
}

.app-loading-screen .home-footer {
  position: absolute;
  bottom: var(--space-md);
  left: 0;
  right: 0;
  margin: 0;
  padding: 0;
  text-align: center;
}

.loader {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 24px;
  margin: 0 auto var(--space-lg);
}

.mark {
  width: 52px;
  height: 52px;
  background: var(--text-primary);
  animation: morph 1.8s ease-in-out infinite;
}

@keyframes morph {
  0%   { border-radius: 10px; transform: rotate(0deg) scale(1); }
  50%  { border-radius: 50%; transform: rotate(180deg) scale(0.82); }
  100% { border-radius: 10px; transform: rotate(360deg) scale(1); }
}

@media (prefers-reduced-motion: reduce) {
  .mark { animation: none; }
}

.loading-spinner {
  width: 36px;
  height: 36px;
  border: 2.5px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  margin: 0 auto var(--space-lg);
  animation: spinCircle 0.8s linear infinite;
}

@keyframes spinCircle {
  to {
    transform: rotate(360deg);
  }
}

.no-results {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-3xl) var(--space-lg);
  text-align: center;
  color: var(--empty-state-color);
  animation: fadeIn 0.3s ease;
}

.no-results__icon {
  width: 60px;
  height: 60px;
  margin-bottom: var(--space-lg);
  opacity: 0.5;
}

.no-results__icon svg {
  width: 100%;
  height: 100%;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.no-results__title {
  font-size: var(--font-size-lg);
  letter-spacing: 2px;
  margin-bottom: var(--space-sm);
}

.no-results__text {
  font-size: var(--font-size-sm);
  letter-spacing: 0.5px;
}

.downloads-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
}

.btn-clear {
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  letter-spacing: 1px;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: color var(--transition-fast), border-color var(--transition-fast), background-color var(--transition-fast);
}

.btn-clear:hover {
  color: var(--text-primary);
  border-color: var(--accent);
  background-color: var(--search-highlight);
}

.download-group {
  margin-bottom: var(--space-xl);
}

.download-group__date {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--border-light);
}

.download-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
}

.download-item__icon {
  width: 36px;
  height: 36px;
  border-radius: var(--border-radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  border: 1.5px solid var(--border-color);
  color: var(--text-primary);
  transition: border-color var(--transition-base), color var(--transition-base);
}

.download-item__info {
  flex: 1;
  min-width: 0;
}

.download-item__name {
  font-size: var(--font-size-sm);
  letter-spacing: 0.5px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.download-item__meta {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
}

.download-item__time {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  flex-shrink: 0;
}

.fab {
  position: fixed;
  bottom: var(--space-xl);
  right: var(--space-xl);
  width: 56px;
  height: 56px;
  border-radius: var(--border-radius-full);
  background-color: var(--fab-bg);
  color: var(--fab-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-base), color var(--transition-base);
  z-index: 200;
  opacity: 0;
  pointer-events: none;
  transform: scale(0.6);
}

.fab.visible {
  opacity: 1;
  pointer-events: auto;
  transform: scale(1);
}

.fab:hover {
  transform: scale(1.1);
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.3);
}

.fab:active {
  transform: scale(0.95);
}

.fab svg {
  width: 24px;
  height: 24px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2.5;
  stroke-linecap: round;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: var(--overlay-bg);
  z-index: 300;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-base);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.modal-overlay.visible {
  opacity: 1;
  pointer-events: auto;
}

.modal {
  background-color: var(--card-bg);
  border-radius: var(--border-radius-lg);
  padding: var(--space-xl);
  width: 90%;
  max-width: 480px;
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.2);
  transform: translateY(20px) scale(0.95);
  transition: transform var(--transition-base), background-color var(--transition-base);
}

.modal-overlay.visible .modal {
  transform: translateY(0) scale(1);
}

.modal__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-lg);
}

.modal__title {
  font-size: var(--font-size-lg);
  letter-spacing: 2px;
}

.modal__close {
  width: 32px;
  height: 32px;
  border-radius: var(--border-radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.modal__close:hover {
  background-color: var(--search-highlight);
}

.modal__close svg {
  width: 18px;
  height: 18px;
  stroke: var(--text-primary);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
}

.form-group {
  margin-bottom: var(--space-lg);
}

.form-group__label {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  letter-spacing: 1px;
  margin-bottom: var(--space-sm);
}

.form-group__input,
.form-group__select {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-base);
  letter-spacing: 0.5px;
}

.form-group__select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23999' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.form-group__select option {
  background-color: var(--card-bg);
  color: var(--text-primary);
}

.form-group__file-input {
  display: none;
}

.form-group__file-label {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-lg);
  border: 2px dashed var(--border-color);
  border-radius: var(--border-radius-md);
  cursor: pointer;
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  letter-spacing: 1px;
  transition: border-color var(--transition-fast), color var(--transition-fast), background-color var(--transition-fast);
}

.form-group__file-label:hover {
  border-color: var(--accent);
  color: var(--text-primary);
  background-color: var(--search-highlight);
}

.drag-active .form-group__file-label {
  border-color: var(--accent);
  background-color: var(--search-highlight);
  color: var(--text-primary);
  transform: scale(1.02);
  border-style: solid;
}

.form-group__file-label.has-file {
  border-style: solid;
  border-color: var(--accent);
  color: var(--text-primary);
}

.form-group__file-label svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.8;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.form-group__new-course {
  margin-top: var(--space-sm);
}

.btn-submit {
  width: 100%;
  padding: var(--space-md);
  font-size: var(--font-size-md);
  letter-spacing: 2px;
  background-color: var(--accent);
  color: var(--bg-primary);
  border-radius: var(--border-radius-sm);
  cursor: pointer;
  transition: opacity var(--transition-fast), transform var(--transition-fast), background-color var(--transition-base), color var(--transition-base);
}

.btn-submit:hover {
  opacity: 0.85;
}

.btn-submit:active {
  transform: scale(0.98);
}

.btn-submit:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.toast {
  position: fixed;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  padding: var(--space-md) var(--space-xl);
  background-color: var(--accent);
  color: var(--bg-primary);
  border-radius: var(--border-radius-sm);
  font-size: var(--font-size-sm);
  letter-spacing: 1px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
  z-index: 400;
  white-space: nowrap;
}

.toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

@media (max-width: 768px) {
  .side-panel {
    position: fixed;
    left: 0;
    top: 0;
    transform: translateX(-100%);
  }

  .side-panel.open {
    transform: translateX(0);
    box-shadow: 4px 0 24px rgba(0, 0, 0, 0.1);
  }

  .mobile-header {
    display: flex;
  }

  .page {
    padding: var(--space-lg) var(--space-lg);
  }

  .page__title {
    font-size: var(--font-size-xl);
  }

  #page-home {
    padding: var(--space-md) var(--space-lg) var(--space-xs);
    min-height: calc(100vh - 60px);
  }

  .home-ascii-art {
    font-size: clamp(2px, 1.4vw, 7px);
    margin-bottom: var(--space-sm);
  }

  .home-info {
    margin-top: var(--space-sm);
    gap: var(--space-sm);
    max-width: 520px;
  }

  .home-mission {
    font-size: var(--font-size-sm);
    line-height: 1.45;
  }

  .home-disclaimer {
    padding: 6px var(--space-sm);
    font-size: 11.5px;
    line-height: 1.4;
  }

  .home-footer {
    padding-top: var(--space-sm);
    padding-bottom: var(--space-xs);
    font-size: 11px;
  }

  .course-grid {
    grid-template-columns: 1fr;
  }

  .fab {
    bottom: var(--space-lg);
    right: var(--space-lg);
  }
}

@media (max-width: 480px) {
  .page {
    padding: var(--space-md);
  }

  #page-home {
    padding: var(--space-sm) var(--space-md) 4px;
    min-height: calc(100vh - 60px);
  }

  .home-ascii-art {
    font-size: clamp(1.8px, 1.8vw, 5px);
    margin-bottom: 4px;
    line-height: 1.15;
  }

  .home-empty__text {
    font-size: 16px;
    letter-spacing: 1.5px;
  }

  .home-empty__subtitle {
    font-size: 12px;
    margin-top: 2px;
  }

  .home-info {
    margin-top: 6px;
    gap: 6px;
  }

  .home-mission {
    font-size: 12px;
    line-height: 1.35;
  }

  .home-disclaimer {
    padding: 5px 8px;
    font-size: 10.5px;
    line-height: 1.3;
    gap: 5px;
  }

  .home-disclaimer__icon {
    width: 13px;
    height: 13px;
    margin-top: 1px;
  }

  .home-footer {
    padding-top: 4px;
    padding-bottom: 4px;
    font-size: 10.5px;
  }

  .search-bar__input {
    font-size: var(--font-size-base);
  }

  .course-card {
    padding: var(--space-md);
  }

  .file-item {
    padding: var(--space-sm) var(--space-md);
  }
}

.panel-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: var(--overlay-bg);
  z-index: 99;
}

@media (max-width: 768px) {
  .panel-overlay.visible {
    display: block;
  }
}

.admin-login__desc {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  letter-spacing: 0.5px;
  margin-bottom: var(--space-lg);
}

.admin-login__status {
  margin-top: var(--space-md);
  font-size: var(--font-size-sm);
  letter-spacing: 0.5px;
  text-align: center;
  min-height: 20px;
  transition: color var(--transition-fast);
}

.admin-login__status--error {
  color: #dc3545;
}

[data-theme="dark"] .admin-login__status--error {
  color: #ff6b7a;
}