/* ═══════════════════════════════════════════════════
   AERA S1 — MINIMAL UI
   Quiet, neutral aesthetic. Dark + light themes.
   ═══════════════════════════════════════════════════ */

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

/* ── Theme variables ─────────────────────────────────
   Single accent: soft indigo. Everything else: layered greys.
   Depth comes from background tone + soft shadows, not borders.
─────────────────────────────────────────────────────── */
:root,
[data-theme="dark"] {
  /* grey layers */
  --bg:           #181818;      /* main canvas — dark gray, not black */
  --surface:      #222222;      /* panels slightly lifted */
  --surface-hi:   #2c2c2c;      /* hover / active layer */
  --surface-lo:   #0f0f0f;      /* sidebar, deeper than main */

  /* borders — very subtle, decorative only */
  --border:       rgba(255,255,255,0.06);
  --border-hi:    rgba(255,255,255,0.10);

  /* text */
  --text:         #ececec;      /* soft white, never pure */
  --text-dim:     #a6a6a6;
  --text-muted:   #6a6a6a;

  /* accent — soft indigo */
  --accent:       #8b7cf6;
  --accent-hi:    #9d90f8;
  --accent-on:    #ffffff;      /* text color on accent bg */
  --accent-soft:  rgba(139,124,246,0.12);
  --accent-softer:rgba(139,124,246,0.06);

  /* bubbles + inputs */
  --user-bubble:  #2c2c2c;
  --ai-bubble:    transparent;
  --input-bg:     #262626;
  --chip-bg:      #242424;

  /* status */
  --danger:       #ef6b6b;
  --success:      #7ec17e;

  /* depth */
  --shadow-xs:    0 1px 2px rgba(0,0,0,0.20);
  --shadow-sm:    0 2px 6px rgba(0,0,0,0.25);
  --shadow:       0 4px 14px rgba(0,0,0,0.30);
  --shadow-lg:    0 18px 50px rgba(0,0,0,0.45);
  --shadow-accent:0 6px 22px rgba(139,124,246,0.22);
}

[data-theme="light"] {
  /* grey layers */
  --bg:           #fafaf9;      /* off-white, warm */
  --surface:      #f2f2f0;      /* panels — light gray */
  --surface-hi:   #e8e8e5;      /* hover / active */
  --surface-lo:   #f5f5f3;      /* sidebar, slightly different from main */

  /* borders — almost invisible */
  --border:       rgba(0,0,0,0.05);
  --border-hi:    rgba(0,0,0,0.09);

  /* text */
  --text:         #1f1f1f;
  --text-dim:     #575757;
  --text-muted:   #8a8a8a;

  /* accent — slightly deeper for contrast on light */
  --accent:       #6b57e0;
  --accent-hi:    #5a46d3;
  --accent-on:    #ffffff;
  --accent-soft:  rgba(107,87,224,0.10);
  --accent-softer:rgba(107,87,224,0.05);

  /* bubbles + inputs */
  --user-bubble:  #ececea;
  --ai-bubble:    transparent;
  --input-bg:     #ffffff;
  --chip-bg:      #f1f1ef;

  /* status */
  --danger:       #d64545;
  --success:      #3aa66d;

  /* depth */
  --shadow-xs:    0 1px 2px rgba(15,15,15,0.04);
  --shadow-sm:    0 2px 8px rgba(15,15,15,0.06);
  --shadow:       0 4px 16px rgba(15,15,15,0.07);
  --shadow-lg:    0 16px 40px rgba(15,15,15,0.10);
  --shadow-accent:0 6px 20px rgba(107,87,224,0.22);
}

:root {
  --sidebar-w:   260px;
  --radius:      12px;
  --radius-sm:   8px;
  --font:        'Inter', system-ui, -apple-system, sans-serif;
  --ease:        cubic-bezier(.4,0,.2,1);
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  min-height: 100vh;
  line-height: 1.6;
  display: flex;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background 0.2s var(--ease), color 0.2s var(--ease);
}

/* Scrollbars */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: transparent; border-radius: 4px; }
*:hover::-webkit-scrollbar-thumb { background: var(--border-hi); }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ═══════════════════════════════════════════════════
   SIDEBAR
   ═══════════════════════════════════════════════════ */

.sidebar {
  width: var(--sidebar-w);
  min-height: 100vh;
  background: var(--surface-lo);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  padding: 0.75rem;
  flex-shrink: 0;
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 50;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease);
}

.sidebar-logo {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.5rem 0.65rem 0.85rem;
}
.logo-gem {
  width: 22px; height: 22px;
  border-radius: 7px;
  background: linear-gradient(135deg, var(--accent), var(--accent-hi));
  flex-shrink: 0;
  box-shadow: var(--shadow-accent);
}
.logo-text {
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: -0.2px;
  color: var(--text);
}

/* New Chat button — subtle accent identity */
.new-chat-btn {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem 0.8rem;
  background: var(--accent-softer);
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--accent);
  font-family: var(--font);
  font-size: 0.86rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s var(--ease), box-shadow 0.15s var(--ease);
  width: 100%;
  text-align: left;
  margin-bottom: 0.85rem;
}
.new-chat-btn:hover {
  background: var(--accent-soft);
  box-shadow: var(--shadow-xs);
}
.new-chat-btn svg { flex-shrink: 0; }

/* Chat history list */
.chat-history-wrap {
  flex: 1;
  overflow-y: auto;
  margin-bottom: 0.5rem;
  padding: 0 0.15rem;
}
.chat-history-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  padding: 0.5rem 0.6rem 0.35rem;
}
.chat-history {
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.chat-history-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.65rem;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-size: 0.82rem;
  font-weight: 400;
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease);
  border: none;
  background: none;
  text-align: left;
  width: 100%;
  font-family: var(--font);
  position: relative;
  white-space: nowrap;
  overflow: hidden;
}
.chat-history-item:hover { background: var(--surface-hi); color: var(--text); }
.chat-history-item.active {
  background: var(--accent-soft);
  color: var(--text);
  font-weight: 500;
}
.chat-history-title {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
}
.chat-history-del {
  opacity: 0;
  width: 20px; height: 20px;
  border-radius: 4px;
  border: none;
  background: none;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: opacity 0.15s, background 0.15s;
  font-size: 0.75rem;
}
.chat-history-item:hover .chat-history-del,
.chat-history-item.active .chat-history-del { opacity: 0.7; }
.chat-history-del:hover { opacity: 1 !important; background: var(--border-hi); color: var(--text); }
.chat-history-empty {
  font-size: 0.78rem;
  color: var(--text-muted);
  padding: 0.6rem 0.65rem;
}

/* Primary navigation */
.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 1px;
  padding-top: 0.35rem;
  border-top: 1px solid var(--border);
  margin-top: 0.25rem;
}
.nav-item {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  padding: 0.55rem 0.7rem;
  border-radius: var(--radius-sm);
  border: none;
  background: none;
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.83rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease);
  text-align: left;
  width: 100%;
}
.nav-item:hover { color: var(--text); background: var(--surface-hi); }
.nav-item.active {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 600;
}
.nav-item.active .nav-icon { opacity: 1; }
.nav-icon {
  font-size: 0.95rem;
  width: 18px;
  text-align: center;
  flex-shrink: 0;
  opacity: 0.85;
}

/* Sidebar footer */
.sidebar-footer {
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
  margin-top: 0.35rem;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}
.sidebar-footer .world-toggle,
.sidebar-footer .theme-toggle {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.55rem 0.7rem;
  cursor: pointer;
  border-radius: var(--radius-sm);
  transition: background 0.15s var(--ease);
  user-select: none;
  width: 100%;
  border: none;
  background: none;
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.82rem;
  font-weight: 500;
}
.sidebar-footer .world-toggle:hover,
.sidebar-footer .theme-toggle:hover { background: var(--accent-soft); color: var(--text); }
.world-toggle-label, .theme-toggle-label {
  flex: 1;
  text-align: left;
}
.world-toggle input { display: none; }
.toggle-track {
  width: 28px; height: 16px;
  background: var(--border-hi);
  border-radius: 999px;
  position: relative;
  transition: background 0.2s var(--ease);
  flex-shrink: 0;
}
.toggle-track::after {
  content: '';
  position: absolute; left: 2px; top: 2px;
  width: 12px; height: 12px;
  background: var(--text);
  border-radius: 50%;
  transition: transform 0.2s var(--ease);
}
.world-toggle input:checked + .toggle-track { background: var(--text-dim); }
.world-toggle input:checked + .toggle-track::after { transform: translateX(12px); background: var(--bg); }

.theme-toggle-icon {
  width: 18px; height: 18px;
  flex-shrink: 0;
  opacity: 0.85;
}

/* ═══════════════════════════════════════════════════
   MAIN CONTENT
   ═══════════════════════════════════════════════════ */

.main {
  margin-left: var(--sidebar-w);
  flex: 1;
  height: 100vh;
  overflow: hidden;
  position: relative;
}

.section {
  position: absolute;
  inset: 0;
  overflow-y: auto;
  padding: 2rem 2.25rem 4rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s var(--ease);
}
.section.active {
  opacity: 1;
  pointer-events: all;
}

/* ═══════════════════════════════════════════════════
   HOME (CHAT) SECTION
   ═══════════════════════════════════════════════════ */

.home-section {
  padding: 0 !important;
  display: flex !important;
  flex-direction: column !important;
  overflow: hidden !important;
}

.home-chat-area {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  padding: 2rem 0 1rem;
  gap: 1.25rem;
  scroll-behavior: smooth;
  width: 100%;
  max-width: 780px;
  margin: 0 auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

/* Welcome state */
.home-welcome {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  flex: 1;
  padding: 3rem 1rem 2rem;
  gap: 0.75rem;
  animation: fadeIn 0.4s var(--ease);
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: none; }
}
.home-welcome-gem {
  width: 42px; height: 42px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent), var(--accent-hi));
  margin-bottom: 0.35rem;
  box-shadow: var(--shadow-accent);
}
.home-welcome-title {
  font-size: 1.6rem;
  font-weight: 600;
  letter-spacing: -0.4px;
  color: var(--text);
}
.home-welcome-sub {
  font-size: 0.92rem;
  color: var(--text-dim);
  max-width: 380px;
  line-height: 1.55;
}

/* Suggestion chips */
.home-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  justify-content: center;
  margin-top: 0.75rem;
}
.home-chip {
  padding: 0.4rem 0.85rem;
  background: var(--chip-bg);
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease), border-color 0.15s var(--ease);
}
.home-chip:hover {
  color: var(--text);
  background: var(--surface-hi);
  border-color: var(--border-hi);
}

/* Quick nav buttons */
.home-quick-nav {
  display: flex;
  gap: 0.5rem;
  margin-top: 0.5rem;
}
.home-quick-btn {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.85rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-muted);
  font-family: var(--font);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
}
.home-quick-btn:hover { color: var(--text); border-color: var(--border-hi); }

/* Chat bubbles — home */
.home-bubble {
  padding: 0.55rem 0;
  font-size: 0.93rem;
  line-height: 1.7;
  animation: fadeIn 0.2s var(--ease);
  max-width: 100%;
}
.home-bubble-user {
  align-self: flex-end;
  background: var(--user-bubble);
  color: var(--text);
  padding: 0.7rem 1rem;
  border-radius: 18px;
  max-width: 80%;
  white-space: pre-wrap;
}
.home-bubble-assistant {
  align-self: stretch;
  background: var(--ai-bubble);
  color: var(--text);
  padding: 0.25rem 0 0.85rem;
}
.home-bubble-meta {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  margin-top: 0.4rem;
  gap: 0.5rem;
}
.home-bubble-tag {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

/* System note */
.home-sys-note {
  align-self: center;
  font-size: 0.78rem;
  color: var(--text-muted);
  padding: 0.3rem 0.85rem;
  animation: fadeIn 0.2s var(--ease);
}

/* Typing indicator — home */
.home-typing {
  display: flex;
  gap: 5px;
  align-items: center;
  align-self: flex-start;
  padding: 0.5rem 0;
  animation: fadeIn 0.2s var(--ease);
}
.home-typing span {
  width: 6px; height: 6px;
  background: var(--text-muted);
  border-radius: 50%;
  animation: bounce 1.1s infinite;
}
.home-typing span:nth-child(2) { animation-delay: 0.15s; }
.home-typing span:nth-child(3) { animation-delay: 0.3s; }
@keyframes bounce {
  0%,80%,100% { transform: translateY(0); opacity: 0.4; }
  40%         { transform: translateY(-4px); opacity: 1; }
}

/* ── Input zone ────────────────────────────────────── */
.home-input-zone {
  flex-shrink: 0;
  padding: 0.5rem 1.5rem 1rem;
  width: 100%;
  max-width: 780px;
  margin: 0 auto;
}

.home-input-box {
  background: var(--input-bg);
  border: 1px solid transparent;
  border-radius: 18px;
  overflow: hidden;
  transition: border-color 0.15s var(--ease), box-shadow 0.2s var(--ease), background 0.15s var(--ease);
  box-shadow: var(--shadow-sm);
}
.home-input-box:focus-within {
  border-color: var(--accent-soft);
  box-shadow: var(--shadow), 0 0 0 3px var(--accent-softer);
}

.home-input-box textarea {
  width: 100%;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.95rem;
  line-height: 1.55;
  padding: 0.95rem 1.1rem 0.35rem;
  resize: none;
  min-height: 50px;
  max-height: 200px;
}
.home-input-box textarea::placeholder { color: var(--text-muted); }

.home-input-footer {
  display: flex;
  align-items: center;
  padding: 0.35rem 0.6rem 0.55rem 0.85rem;
  gap: 0.35rem;
}

.home-media-btns { display: flex; gap: 0.2rem; }
.home-media-btn {
  width: 32px; height: 32px;
  display: flex; align-items: center; justify-content: center;
  background: none;
  border: none;
  border-radius: 8px;
  color: var(--text-muted);
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease);
}
.home-media-btn:hover {
  color: var(--text);
  background: var(--accent-soft);
}
.home-media-btn.recording {
  color: var(--danger);
  background: rgba(239,107,107,0.1);
}

.home-file-badge {
  display: none;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.6rem;
  background: var(--accent-soft);
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 0.74rem;
  color: var(--text-dim);
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.home-file-badge.show { display: flex; }
.home-file-badge button {
  background: none; border: none; color: var(--text-dim);
  cursor: pointer; font-size: 0.7rem; flex-shrink: 0;
  opacity: 0.6;
}
.home-file-badge button:hover { opacity: 1; }

/* Send button — accent */
.home-send-btn {
  margin-left: auto;
  width: 34px; height: 34px;
  border-radius: 9px;
  background: var(--accent);
  border: none;
  color: var(--accent-on);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: background 0.15s var(--ease), box-shadow 0.15s var(--ease), transform 0.1s var(--ease);
  flex-shrink: 0;
  box-shadow: var(--shadow-accent);
}
.home-send-btn:hover:not(:disabled) { background: var(--accent-hi); }
.home-send-btn:active { transform: scale(0.94); }
.home-send-btn:disabled { opacity: 0.35; cursor: not-allowed; box-shadow: none; }
.home-send-btn .spinner { border-color: rgba(255,255,255,0.25); border-top-color: #fff; }

.home-input-hint {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: center;
  margin-top: 0.55rem;
}

.status-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--success);
  flex-shrink: 0;
}

/* ═══════════════════════════════════════════════════
   NOTES + Q&A SECTION
   ═══════════════════════════════════════════════════ */

.section-title {
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: -0.3px;
  margin-bottom: 0.3rem;
}
.section-sub {
  font-size: 0.88rem;
  color: var(--text-dim);
  margin-bottom: 1.5rem;
}

.input-panel {
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  overflow: hidden;
  margin-bottom: 1.25rem;
  transition: border-color 0.15s var(--ease), box-shadow 0.2s var(--ease);
  box-shadow: var(--shadow-xs);
}
.input-panel:focus-within {
  border-color: var(--accent-soft);
  box-shadow: var(--shadow-sm), 0 0 0 3px var(--accent-softer);
}

.input-panel textarea {
  width: 100%;
  min-height: 140px;
  max-height: 320px;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.92rem;
  line-height: 1.6;
  padding: 1rem 1.1rem 0.4rem;
  resize: none;
}
.input-panel textarea::placeholder { color: var(--text-muted); }

.input-toolbar {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 0.85rem;
  border-top: 1px solid var(--border);
}
.input-tool-btn {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.4rem 0.75rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
  white-space: nowrap;
}
.input-tool-btn:hover {
  color: var(--text);
  border-color: var(--border-hi);
  background: var(--accent-soft);
}
.input-tool-btn.recording {
  color: var(--danger);
  border-color: var(--danger);
}
.input-tool-btn.active-upload {
  color: var(--text);
  border-color: var(--border-hi);
}
.toolbar-spacer { flex: 1; }
.generate-btn {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.5rem 1.05rem;
  background: var(--accent);
  color: var(--accent-on);
  border: none;
  border-radius: 8px;
  font-family: var(--font);
  font-size: 0.83rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s var(--ease), box-shadow 0.15s var(--ease);
  box-shadow: var(--shadow-accent);
}
.generate-btn:hover:not(:disabled) { background: var(--accent-hi); }
.generate-btn:disabled { opacity: 0.35; cursor: not-allowed; box-shadow: none; }

.file-badge {
  display: none;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.7rem;
  background: var(--accent-soft);
  border: 1px solid var(--border);
  border-radius: 7px;
  font-size: 0.78rem;
  color: var(--text-dim);
}
.file-badge.show { display: flex; }
.file-badge-close {
  cursor: pointer;
  opacity: 0.6;
  font-size: 0.7rem;
  margin-left: 0.15rem;
}
.file-badge-close:hover { opacity: 1; }

.output-area { display: none; }
.output-area.show { display: block; animation: fadeIn 0.3s var(--ease); }

.output-panel {
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  margin-bottom: 1.25rem;
  overflow: hidden;
  box-shadow: var(--shadow-xs);
}
.output-panel-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.1rem;
  border-bottom: 1px solid var(--border);
}
.output-panel-title {
  font-size: 0.76rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  flex: 1;
}
.output-panel-body {
  padding: 1.2rem 1.25rem;
  font-size: 0.92rem;
  line-height: 1.75;
  white-space: pre-wrap;
  min-height: 60px;
}
.output-panel-body strong { color: var(--text); font-weight: 600; }

.restyle-bar {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1rem;
}
.restyle-input {
  flex: 1;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 0.85rem;
  padding: 0.55rem 0.95rem;
  outline: none;
  transition: border-color 0.15s var(--ease), box-shadow 0.15s var(--ease);
}
.restyle-input:focus {
  border-color: var(--accent-soft);
  box-shadow: 0 0 0 3px var(--accent-softer);
}
.restyle-input::placeholder { color: var(--text-muted); }
.restyle-btn {
  padding: 0.5rem 0.95rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.83rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
  white-space: nowrap;
  display: flex; align-items: center; gap: 0.4rem;
}
.restyle-btn:hover { color: var(--text); border-color: var(--border-hi); }
.restyle-btn:disabled { opacity: 0.35; cursor: not-allowed; }
.restyle-btn .spinner { border-color: var(--border); border-top-color: var(--text-dim); }
.restyle-btn.loading .spinner { display: inline-block; }
.restyle-btn.loading .btn-label { display: none; }

/* Chat wrap (Notes Q&A) */
.chat-wrap {
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-xs);
}
.chat-head {
  padding: 0.7rem 1.1rem;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.chat-head-title {
  font-size: 0.76rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
}
.chat-messages {
  padding: 1.1rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  min-height: 200px;
  max-height: 400px;
  overflow-y: auto;
}
.chat-empty-msg {
  color: var(--text-muted);
  font-size: 0.88rem;
  text-align: center;
  padding: 2.5rem 0;
}
.bubble {
  max-width: 85%;
  padding: 0.7rem 0.95rem;
  border-radius: 14px;
  font-size: 0.9rem;
  line-height: 1.6;
  animation: fadeIn 0.2s var(--ease);
}
.bubble.user {
  align-self: flex-end;
  background: var(--user-bubble);
  color: var(--text);
}
.bubble.assistant {
  align-self: flex-start;
  background: var(--surface-hi);
  white-space: pre-wrap;
  position: relative;
  padding-bottom: 1.7rem;
  box-shadow: var(--shadow-xs);
}
.bubble-copy {
  position: absolute;
  bottom: 0.4rem;
  right: 0.6rem;
}
.bubble-tag {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-top: 0.3rem;
  display: block;
}

/* Chart & diagram containers */
.svg-diagram {
  margin: 0.85rem 0;
  padding: 0.9rem;
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  display: flex;
  justify-content: center;
  overflow-x: auto;
  box-shadow: var(--shadow-xs);
}
.svg-diagram svg {
  max-width: 100%;
  height: auto;
}
.chart-wrap {
  position: relative;
  width: 100%;
  height: 260px;
  margin: 0.85rem 0;
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 0.95rem;
  box-shadow: var(--shadow-xs);
}
.chart-wrap canvas {
  width: 100% !important;
  height: 100% !important;
}

/* Streaming cursor — shows while assistant is typing */
.stream-cursor {
  display: inline-block;
  width: 7px;
  height: 1em;
  vertical-align: -2px;
  background: var(--accent);
  margin-left: 2px;
  border-radius: 1px;
  animation: stream-blink 0.95s steps(2, start) infinite;
  opacity: 0.85;
}
@keyframes stream-blink {
  to { opacity: 0; }
}

.typing-indicator {
  display: flex;
  gap: 5px;
  align-items: center;
  padding: 0.7rem 0.95rem;
  background: var(--surface-hi);
  border-radius: 14px;
  align-self: flex-start;
  animation: fadeIn 0.2s var(--ease);
}
.typing-indicator span {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--text-muted);
  animation: bounce 1.1s infinite;
}
.typing-indicator span:nth-child(2) { animation-delay: 0.15s; }
.typing-indicator span:nth-child(3) { animation-delay: 0.3s; }

.chat-input-area {
  padding: 0.75rem;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 0.55rem;
  align-items: flex-end;
}
.chat-input-area textarea {
  flex: 1;
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.9rem;
  line-height: 1.5;
  padding: 0.6rem 0.9rem;
  resize: none;
  outline: none;
  min-height: 40px;
  max-height: 130px;
  transition: border-color 0.15s var(--ease), box-shadow 0.15s var(--ease);
}
.chat-input-area textarea:focus {
  border-color: var(--accent-soft);
  box-shadow: 0 0 0 3px var(--accent-softer);
}
.chat-input-area textarea::placeholder { color: var(--text-muted); }
.send-btn {
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--accent);
  border: none;
  color: var(--accent-on);
  font-size: 0.9rem;
  cursor: pointer;
  flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.15s var(--ease), box-shadow 0.15s var(--ease), transform 0.1s var(--ease);
  box-shadow: var(--shadow-accent);
}
.send-btn:hover:not(:disabled) { background: var(--accent-hi); }
.send-btn:active { transform: scale(0.94); }
.send-btn:disabled { opacity: 0.35; cursor: not-allowed; box-shadow: none; }
.send-btn .spinner { border-color: rgba(255,255,255,0.25); border-top-color: #fff; }

/* ═══════════════════════════════════════════════════
   FLASHCARD SECTION
   ═══════════════════════════════════════════════════ */

.fc-section-inner {
  max-width: 680px;
  margin: 0 auto;
}

.fc-deck-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.75rem;
}
.fc-deck-info h2 {
  font-size: 1.35rem;
  font-weight: 600;
  letter-spacing: -0.3px;
}
.fc-deck-info p {
  font-size: 0.82rem;
  color: var(--text-dim);
  margin-top: 0.15rem;
}
.fc-deck-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.toggle-small {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  cursor: pointer;
  user-select: none;
  font-size: 0.82rem;
  color: var(--text-dim);
}
.toggle-small input { display: none; }
.toggle-small input:checked + .toggle-track { background: var(--text-dim); }
.toggle-small input:checked + .toggle-track::after { transform: translateX(12px); background: var(--bg); }

.fc-stage {
  position: relative;
  perspective: 1400px;
  height: 320px;
  margin-bottom: 1.5rem;
  cursor: pointer;
}
.fc-card-3d {
  width: 100%; height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s cubic-bezier(.4,0,.2,1);
  border-radius: var(--radius);
}
.fc-card-3d.flipped { transform: rotateY(180deg); }

@keyframes fcSlideRight {
  from { opacity: 0; transform: translateX(30px); }
  to   { opacity: 1; transform: none; }
}
@keyframes fcSlideLeft {
  from { opacity: 0; transform: translateX(-30px); }
  to   { opacity: 1; transform: none; }
}
.fc-stage.slide-r .fc-card-3d { animation: fcSlideRight 0.25s var(--ease); }
.fc-stage.slide-l .fc-card-3d { animation: fcSlideLeft  0.25s var(--ease); }

.fc-face {
  position: absolute; inset: 0;
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2.25rem;
  text-align: center;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}
.fc-face-front {
  background: var(--surface);
  border: 1px solid transparent;
  box-shadow: var(--shadow-lg);
  transition: box-shadow 0.2s var(--ease);
}
.fc-face-front:hover { box-shadow: var(--shadow-lg), 0 0 0 1px var(--accent-soft); }
.fc-face-back {
  background: var(--surface-hi);
  border: 1px solid transparent;
  box-shadow: var(--shadow-lg), inset 0 0 0 1px var(--accent-soft);
  transform: rotateY(180deg);
}
.fc-face-label {
  font-size: 0.66rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 1rem;
}
.fc-face-text {
  font-size: 1.15rem;
  font-weight: 500;
  line-height: 1.5;
  max-width: 520px;
  color: var(--text);
}
.fc-face-back .fc-face-text {
  font-weight: 400;
  font-size: 1rem;
  color: var(--text-dim);
}
.fc-hint-bottom {
  position: absolute;
  bottom: 1.1rem;
  font-size: 0.68rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

.fc-progress-bar {
  height: 2px;
  background: var(--border);
  border-radius: 999px;
  margin-bottom: 1.25rem;
  overflow: hidden;
}
.fc-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-hi));
  border-radius: 999px;
  transition: width 0.3s var(--ease);
}

.fc-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  margin-bottom: 1.75rem;
}
.fc-btn {
  padding: 0.5rem 1.2rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
}
.fc-btn:hover:not(:disabled) {
  color: var(--text);
  border-color: var(--border-hi);
}
.fc-btn:disabled { opacity: 0.25; cursor: not-allowed; }
.fc-btn.danger-btn { color: var(--text-muted); }
.fc-btn.danger-btn:hover { color: var(--danger); border-color: var(--danger); }

.fc-confirm-row {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.82rem;
  color: var(--text-dim);
}
.fc-yes-btn, .fc-no-btn {
  padding: 0.35rem 0.75rem;
  border-radius: 6px;
  border: none;
  font-family: var(--font);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: opacity 0.15s;
}
.fc-yes-btn { background: var(--danger); color: #fff; }
.fc-no-btn  { background: var(--surface-hi); color: var(--text-dim); border: 1px solid var(--border); }

.fc-kbd-hints {
  text-align: center;
  font-size: 0.73rem;
  color: var(--text-muted);
  margin-bottom: 1.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
}
.kbd {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.15rem 0.45rem;
  background: var(--surface-hi);
  border: 1px solid var(--border);
  border-radius: 5px;
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-right: 0.25rem;
}

.fc-add-card {
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 1.2rem;
  box-shadow: var(--shadow-xs);
}
.fc-add-title {
  font-size: 0.76rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-dim);
  margin-bottom: 0.85rem;
}
.fc-add-fields {
  display: flex;
  gap: 0.6rem;
  margin-bottom: 0.7rem;
}
.fc-add-fields input {
  flex: 1;
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-family: var(--font);
  font-size: 0.88rem;
  padding: 0.6rem 0.95rem;
  outline: none;
  transition: border-color 0.15s var(--ease), box-shadow 0.15s var(--ease);
}
.fc-add-fields input:focus {
  border-color: var(--accent-soft);
  box-shadow: 0 0 0 3px var(--accent-softer);
}
.fc-add-fields input::placeholder { color: var(--text-muted); }
.fc-add-submit {
  padding: 0.55rem 1.15rem;
  background: var(--accent);
  color: var(--accent-on);
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.83rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s var(--ease), box-shadow 0.15s var(--ease);
  box-shadow: var(--shadow-accent);
}
.fc-add-submit:hover { background: var(--accent-hi); }

/* ═══════════════════════════════════════════════════
   CAMERA MODAL
   ═══════════════════════════════════════════════════ */

.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.5);
  backdrop-filter: blur(4px);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s var(--ease);
}
.modal-overlay.show {
  opacity: 1;
  pointer-events: all;
}
.modal-box {
  background: var(--surface);
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 1.5rem;
  width: 90%;
  max-width: 540px;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.25s var(--ease);
}
@keyframes modalIn {
  from { opacity: 0; transform: scale(0.97) translateY(6px); }
  to   { opacity: 1; transform: none; }
}
.modal-title {
  font-size: 0.95rem;
  font-weight: 600;
}
.modal-video {
  width: 100%;
  border-radius: var(--radius-sm);
  background: #000;
  aspect-ratio: 4/3;
  object-fit: cover;
}
.modal-actions {
  display: flex;
  gap: 0.55rem;
  justify-content: flex-end;
}

/* ═══════════════════════════════════════════════════
   SHARED COMPONENTS
   ═══════════════════════════════════════════════════ */

.btn-outline {
  display: inline-flex; align-items: center; gap: 0.3rem;
  padding: 0.35rem 0.75rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.76rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
}
.btn-outline:hover { color: var(--text); border-color: var(--border-hi); }
.btn-outline.copied { color: var(--success); border-color: var(--success); }

.btn-solid {
  display: inline-flex; align-items: center; gap: 0.35rem;
  padding: 0.5rem 1.05rem;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-family: var(--font);
  font-size: 0.84rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s var(--ease);
}
.btn-solid:hover { color: var(--text); border-color: var(--border-hi); }
.btn-solid:disabled { opacity: 0.3; cursor: not-allowed; }
.btn-solid.primary {
  background: var(--accent);
  border-color: transparent;
  color: var(--accent-on);
  box-shadow: var(--shadow-accent);
}
.btn-solid.primary:hover { background: var(--accent-hi); }

.spinner {
  width: 14px; height: 14px;
  border: 2px solid var(--border);
  border-top-color: var(--text);
  border-radius: 50%;
  animation: spin 0.65s linear infinite;
  display: none; flex-shrink: 0;
}
.loading .spinner { display: inline-block; }
.loading .btn-label { display: none; }
@keyframes spin { to { transform: rotate(360deg); } }

.skeleton {
  background: linear-gradient(90deg, var(--surface) 25%, var(--surface-hi) 50%, var(--surface) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.4s infinite;
  border-radius: 4px;
  height: 12px;
  margin-bottom: 0.55rem;
}
@keyframes shimmer { to { background-position: -200% 0; } }

.err-msg {
  background: rgba(239,107,107,0.08);
  border: 1px solid rgba(239,107,107,0.25);
  color: var(--danger);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.95rem;
  font-size: 0.85rem;
  display: none;
  margin-top: 0.5rem;
}

/* ═══════════════════════════════════════════════════
   RESPONSIVE
   ═══════════════════════════════════════════════════ */

@media (max-width: 768px) {
  :root { --sidebar-w: 0px; }
  .sidebar {
    width: 100%;
    height: 56px;
    flex-direction: row;
    top: auto; bottom: 0; left: 0; right: 0;
    border-right: none;
    border-top: 1px solid var(--border);
    padding: 0 0.5rem;
    align-items: center;
  }
  .sidebar-logo, .new-chat-btn, .chat-history-wrap, .sidebar-footer { display: none; }
  .sidebar-nav { flex-direction: row; flex: 1; justify-content: space-around; gap: 0; padding: 0; border: none; margin: 0; }
  .nav-item { flex-direction: column; gap: 0.12rem; font-size: 0.68rem; padding: 0.35rem; align-items: center; justify-content: center; }
  .main { margin-left: 0; margin-bottom: 56px; }
  .section { padding: 1.25rem 1rem 3.5rem; }
  .home-section { padding: 0 !important; }
  .home-chat-area { padding: 1.25rem 1rem 0.75rem; }
  .home-input-zone { padding: 0.5rem 1rem 0.75rem; }
  .home-welcome-title { font-size: 1.4rem; }
  .fc-face-text { font-size: 0.95rem; }
  .fc-stage { height: 280px; }
}