:root {
  /* palette */
  --color-bg: #0f1419;
  --color-surface: #1a202c;
  --color-surface-alt: #2d3748;
  --color-border: #4a5568;
  --color-text: #e2e8f0;
  --color-text-muted: #a0aec0;
  --color-accent: #8b9d77;
  --color-accent-strong: #5a6b47;
  --color-accent-soft: #4a5d3a;
  --color-secondary: #075e5e;
  --color-secondary-strong: #0a8453;
  --color-error: #f56565;
  --color-success: #48bb78;
  --color-warning: #ff9800;

  /* typography */
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen",
    "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue",
    sans-serif;
  --font-size-xs: 0.8rem;
  --font-size-sm: 0.9rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: clamp(2.4rem, 4vw, 3.4rem);

  /* spacing scale */
  --space-2xs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 0.7rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  /* radii & shadows */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1.5rem;
  --radius-pill: 0.5px;
  --shadow-soft: 0 8px 24px rgba(15, 20, 25, 0.2);
  --shadow-strong: 0 16px 40px rgba(15, 20, 25, 0.28);
  --connection-status-font: clamp(0.85rem, 1vw, 1rem);

  /* chat layout */
  --sidebar-width-min: 18rem;
  --sidebar-width-max: 24rem;
  --sidebar-width: clamp(var(--sidebar-width-min), 22vw, var(--sidebar-width-max));
  --chat-header-min-height: clamp(3.5rem, 5vw, 4.5rem);
  --chat-input-min-height: clamp(3.1rem, 4.5vw, 3.9rem);
  --chat-input-max-height: clamp(3.9rem, 16vh, 8rem);
  --messages-gutter: clamp(1rem, 3vw, 2.5rem);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  background: var(--color-bg);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  display: block;
  max-width: 100%;
}

button,
input,
textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

#root {
  min-height: 100vh;
  width: 100vw;
  overflow-x: hidden;
  display: flex;
  flex-direction: column;
}

.app {
  flex: 1;
  display: flex;
  flex-direction: column;
  width: 100%;
}

.app.app--chat {
  overflow: hidden;
}

body.no-scroll {
  overflow: hidden;
  height: 100vh;
}

/* -------------------------------------------------------------------------- */
/* generic layout blocks                                                       */
/* -------------------------------------------------------------------------- */

.page {
  width: min(100%, 62.5rem);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.page.chat-room-page {
  width: 100%;
  margin: 0;
  padding: 0;
  gap: 0;
}

.page-header {
  display: grid; /* USE GRID! */
  grid-template-columns: auto auto auto; /* Three columns */
  align-items: center; /* Vertically center items */
  gap: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.page-header h2 {
  grid-column: 2;
  margin: 0;
  font-size: clamp(1.4rem, 2vw, 1.8rem);
  text-align: center;
}

.back-btn,
.send-button,
.emoji-button,
.sidebar-btn,
.menu-action-btn,
.action-button,
.file-download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  grid-column: 1;
  gap: var(--space-xs);
  padding: 0.1rem var(--space-xs);
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  min-height: 2.75rem;
  min-width: 2.75rem;
}

.mobile-menu-btn,
.mobile-menu-toggle,
.close-sidebar-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  grid-column: 1;
  gap: var(--space-xs);
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  width: clamp(2.5rem, 3.75vw, 3.4rem);
  height: clamp(2.5rem, 3.75vw, 3.4rem);
  padding: var(--space-2xs);
}

.chat-main-header .mobile-menu-toggle {
  justify-self: flex-start;
  align-self: center;
  width: clamp(2.5rem, 3.75vw, 3.2rem);
  height: clamp(2.5rem, 3.75vw, 3.2rem);
}

.back-btn,
.mobile-menu-btn,
.mobile-menu-toggle,
.menu-action-btn,
.sidebar-btn {
  background: var(--color-secondary);
}

.send-button:hover:not(:disabled),
.emoji-button:hover,
.action-button:hover,
.file-download-btn:hover,
.sidebar-btn:hover,
.menu-action-btn:hover,
.back-btn:hover,
.mobile-menu-btn:hover,
.mobile-menu-toggle:hover,
.close-sidebar-btn:hover {
  background: var(--color-accent-strong);
  transform: translateY(-1px);
  box-shadow: var(--shadow-soft);
}

.send-button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.emoji-button {
  background: #ff6b6b;
}

.hero {
  text-align: center;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 40rem;
  max-height: 30vh;
}

.hero h1 {
  font-size: var(--font-size-xl);
  margin: 0;
  font-weight: 700;
  line-height: 1.1;
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-strong) 55%, var(--color-accent-soft) 100%);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero p {
  margin: 0;
  font-size: clamp(1rem, 1.5vw, 1.15rem);
  color: rgba(226, 232, 240, 0.85);
}

.subtitle {
  margin-top: var(--space-sm);
  font-style: italic;
  color: var(--color-text-muted);
}

.mini-version-badge {
  align-items: center;
  text-align: center;
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.section,
.info-card {
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
}

.info-card {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
}

.info-card i {
  color: var(--color-success);
}

.join-container,
.host-container,
.demo-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  width: 100%;
}

.button-grid {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: var(--space-md);
}

.page-button {
  display: flex;
  align-items: center;
  height: clamp(6rem, 20vw, 8rem);
  width: 90vw;
  gap: var(--space-md);
  padding: var(--space-lg);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #081f42 0%, #380521 100%);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.page-button i {
  font-size: 2rem;
  width: 3rem;
  text-align: center;
}

.page-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-soft);
}

.host-btn,
.host-action {
  border-color: var(--color-success);
  color: #fff;
}

.join-btn,
.join-action {
  border-color: #2196f3;
  color: #fff;
}

demo-btn,
.demo-action {
  border-color: var(--color-warning);
  color: #fff;
}

.action-button {
  align-self: center;
  background: #007bff;
}

.action-button i {
  font-size: 1.2rem;
}

.input-group {
  display: flex;
  gap: var(--space-sm);
}

.peer-id-input {
  flex: 1;
}

.input-textbox,
.message-input,
.chat-message-input-desktop,
.chat-textarea {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  transition: border-color 0.2s ease;
}

.input-textbox:focus,
.message-input:focus,
.chat-message-input-desktop:focus,
.chat-textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}

.notification {
  position: fixed;
  inset: var(--space-md) var(--space-md) auto auto;
  width: clamp(18rem, 20vw, 24rem);
  background: var(--color-surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-strong);
  transform: translateX(120%);
  transition: transform 0.25s ease;
  z-index: 1000;
}

.notification-show {
  transform: translateX(0);
}

.notification-content {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  color: #fff;
}

.notification-content i:first-child {
  font-size: 1.25rem;
}

.notification-info {
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-strong) 100%);
}

.notification-success {
  background: linear-gradient(135deg, #4caf50 0%, #2f855a 100%);
}

.notification-error {
  background: linear-gradient(135deg, #f44336 0%, #c53030 100%);
}

.notification-warning {
  background: linear-gradient(135deg, #ff9800 0%, #b7791f 100%);
}

.notification-close {
  padding: var(--space-2xs);
  border-radius: var(--radius-sm);
}

/* -------------------------------------------------------------------------- */
/* chat layout                                                                */
/* -------------------------------------------------------------------------- */

.chat-room-page {
  flex: 1;
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-height: 100vh;
  overflow: hidden;
}

.chat-container-desktop {
  flex: 1;
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  background: var(--color-surface);
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  min-height: 0;
  height: 100%;
}

.mobile-sidebar-backdrop {
  display: none;
}

.chat-sidebar {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
  padding: var(--space-lg);
  background: var(--color-surface-alt);
  border-right: 1px solid var(--color-border);
  width: var(--sidebar-width);
  min-width: var(--sidebar-width-min);
  max-width: var(--sidebar-width-max);
  transform: translateX(0);
  transition: transform 0.25s ease, opacity 0.2s ease, visibility 0.2s ease;
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.chat-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding: var(--space-md);
  border-radius: var(--radius-sm);
  background: rgba(15, 20, 25, 0.5);
}

.chat-info h4 {
  margin: 0;
  display: flex;
  gap: var(--space-xs);
  align-items: center;
  font-size: 1rem;
}

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

.sidebar-btn {
  justify-content: flex-start;
  width: 100%;
}

.chat-main {
  display: flex;
  flex-direction: column;
  background: var(--color-surface);
  min-height: 0;
  height: 100%;
}

.chat-main-header {
  display: grid;
  grid-template-columns: auto auto auto;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  padding: 0 var(--space-sm);
  min-height: var(--chat-header-min-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface-alt);
  flex-shrink: 0;
}

.chat-main-header .mobile-menu-toggle {
  justify-self: flex-start;
  align-self: center;
  width: auto;
  max-width: 3.25rem;
  min-width: 2.5rem;
}


.room-info h3 {
  margin: 0;
  font-size: clamp(1rem, 2.2vw, 4rem);
  font-weight: 600;
  word-break: break-all;
  grid-column: 2;
  text-align: center;
}

.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  justify-self: flex-end;
}

.connection-status {
  display: flex;
  align-items: center;
  gap: var(--space-2xs);
  font-size: clamp(0.95rem, 1.4vw, 1.35rem);
  line-height: 1.1;
}

.connection-status .connected {
  color: var(--color-accent);
}

.connection-status .disconnected {
  color: var(--color-error);
}

.chat-messages-desktop {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: var(--messages-gutter);
  padding-bottom: 0;
  overflow: hidden;
  min-height: 0;
  height: 100%;
  max-height: 100%;
}

.messages-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  overflow-y: auto;
  padding: 0;
  scroll-behavior: smooth;
  min-height: 0;
  overscroll-behavior: contain;
  max-height: 100%;
}

.message-placeholder {
  flex-direction: column;
  display: flex;
  place-items: center;
  align-items: center;
  gap: var(--space-xs);
  color: var(--color-text-muted);
  text-align: center;
  padding: var(--space-lg);
}

/* message appearance -------------------------------------------------------- */

:root {
  --message-gap: clamp(0.4rem, 1.5vw, 0.7rem);
  --message-padding-x: clamp(0.55rem, 1.8vw, 1.2rem);
  --message-avatar-size: clamp(2rem, 3vw, 2.6rem);
  --message-avatar-font: clamp(0.7rem, 1.1vw, 0.9rem);
  --message-header-gap: var(--space-xs);
  --message-header-spacing: var(--space-2xs);
}

.message {
  display: flex;
  gap: var(--message-gap);
  padding: var(--space-2xs) var(--message-padding-x);
  border-radius: var(--radius-sm);
  transition: background 0.15s ease;
}

.message:hover {
  background: rgba(255, 255, 255, 0.04);
}

.message.no-avatar {
  padding-left: calc(
    var(--message-padding-x) + var(--message-avatar-size) + var(--message-gap)
  );
}

.message-avatar {
  width: var(--message-avatar-size);
  height: var(--message-avatar-size);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #5865f2 0%, #4752c4 100%);
  font-size: var(--message-avatar-font);
  color: #fff;
  font-weight: 600;
  flex-shrink: 0;
  margin-top: var(--space-2xs);
}

.own-message .message-avatar {
  background: linear-gradient(135deg, #00d4aa 0%, #009d7c 100%);
}

.message-content-wrapper {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  min-width: 0;
}

.message-header {
  display: flex;
  align-items: baseline;
  gap: var(--message-header-gap);
  margin-bottom: var(--message-header-spacing);
}

.message-sender {
  font-weight: 600;
  font-size: var(--font-size-sm);
}

.message-time {
  font-size: var(--font-size-xs);
  color: rgba(226, 232, 240, 0.6);
}

.message-content {
  font-size: var(--font-size-sm);
  line-height: 1.4;
  word-break: break-word;
}

.system-message {
  font-style: italic;
  opacity: 0.85;
}

.media-message {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  position: relative;
}

.media-message img,
.media-message video {
  max-width: min(100%, 16rem);
  max-height: 12.5rem;
  border-radius: var(--radius-md);
  object-fit: contain;
  box-shadow: var(--shadow-soft);
}

.image-download-btn {
  position: absolute;
  top: var(--space-xs);
  right: var(--space-xs);
  width: 2rem;
  height: 2rem;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.75);
  opacity: 0;
  transition: opacity 0.2s ease;
}

.media-message:hover .image-download-btn {
  opacity: 1;
}

.file-attachment {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.08);
}

.file-upload-btn {
  font-size: 1.25rem;
  padding: 0.25em;
  color: var(--color-accent);
}

.file-attachment strong {
  display: block;
  color: var(--color-text);
}

.file-attachment small {
  color: var(--color-text-muted);
  font-size: var(--font-size-xs);
}

/* user list ---------------------------------------------------------------- */

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

.user-list-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  max-height: 16rem;
  overflow-y: auto;
  padding-right: var(--space-2xs);
}

.user-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  background: rgba(15, 20, 25, 0.45);
}

.user-avatar {
  width: 2rem;
  height: 2rem;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-strong) 100%);
  font-size: var(--font-size-xs);
  color: #fff;
}

.user-info {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-2xs);
  min-width: 0;
}

.user-name {
  display: flex;
  align-items: center;
  gap: var(--space-2xs);
  font-weight: 500;
  font-size: var(--font-size-sm);
}

.host-badge,
.you-badge {
  display: inline-flex;
  align-items: center;
  padding: 0 var(--space-xs);
  border-radius: var(--radius-pill);
  font-size: var(--font-size-xs);
}

.host-badge {
  background: linear-gradient(135deg, #ffd700 0%, #ffb347 100%);
  color: #1a202c;
}

.you-badge {
  background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-strong) 100%);
  color: #fff;
}

.user-joined {
  font-size: var(--font-size-xs);
  color: rgba(226, 232, 240, 0.6);
}

/* input bar ---------------------------------------------------------------- */

.chat-input-desktop {
  position: sticky;
  bottom: 0;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75em var(--messages-gutter);
  min-height: calc(var(--chat-input-min-height) + var(--space-2xs));
  max-height: var(--chat-input-max-height);
  overflow: hidden;
  background: rgba(26, 32, 44, 0.98);
  border-top: 1px solid var(--color-border);
  flex-shrink: 0;
}

.chat-message-input-desktop,
.chat-textarea {
  flex: 1;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-border);
  padding: 0.75em 1.25em;
}

.chat-textarea {
  resize: none;
  min-height: calc(1.5em + 1.5rem);
  max-height: calc(var(--chat-input-max-height) - 1.5rem);
  overflow-y: auto;
}

/* legacy fallback ----------------------------------------------------------- */

.chat-container {
  display: flex;
  flex-direction: column;
  height: 60vh;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.chat-messages {
  flex: 1;
  display: grid;
  place-items: center;
  padding: var(--space-md);
  background: rgba(255, 255, 255, 0.05);
}

@media (min-width: 64.01rem) {
  .chat-container-desktop.sidebar-collapsed {
    grid-template-columns: 0 minmax(0, 1fr);
  }

  .chat-container-desktop.sidebar-collapsed .chat-sidebar {
    transform: translateX(-100%);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    overflow: hidden;
  }
}

/* overlay ------------------------------------------------------------------- */

.image-overlay {
  position: fixed;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.75);
  z-index: 1010;
}

.image-overlay.open {
  display: flex;
}

.image-overlay .overlay-content {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 90vw;
  max-height: 80vh;
}

.image-overlay img {
  max-height: 70vh;
  border-radius: var(--radius-md);
}

/* -------------------------------------------------------------------------- */
/* media queries                                                              */
/* -------------------------------------------------------------------------- */

@media (max-width: 64rem) {
  .page {
    padding-inline: var(--space-md);
  }

  .chat-container-desktop {
    grid-template-columns: minmax(0, 1fr);
  }

  .chat-sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    transform: translateX(-100%);
    width: clamp(var(--sidebar-width-min), 10vw, 100vw);
    max-width: 100vw;
    z-index: 999;
    box-shadow: var(--shadow-strong);
    transition: transform 0.25s ease;
  }

  .chat-sidebar.mobile-open {
    transform: translateX(0);
  }

  .mobile-sidebar-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(15, 20, 25, 0.55);
    z-index: 998;
  }

  .mobile-menu-btn {
    display: inline-flex;
  }

  .chat-input-desktop {
    padding-inline: var(--space-md);
  }

  .chat-messages-desktop {
    padding: var(--space-md);
  }
}

@media (max-width: 40rem) {
  .page {
    padding: var(--space-lg) var(--space-sm);
  }


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

  .button-grid {
    gap: var(--space-sm);
  }

  .chat-main-header {
    padding-inline: var(--space-md);
  }

  .message {
    padding-inline: var(--space-sm);
  }
}