/* ============================================================
   NextResearchAI Design System — design tokens + shared components
   ============================================================ */

/* --- Tokens --- */
:root {
  --sb-bg: #ffffff;
  --sb-hover: #edf2ee;
  --sb-text: #17201d;
  --sb-muted: #69746f;
  --sb-border: #dce2dc;
  --sb-soft: #f4f7f4;
  --sb-active-bg: rgba(15,143,114,0.12);
  --sb-active-text: #0f8f72;
  --main-bg: #f6f7f4;
  --card-bg: #ffffff;
  --input-bg: #f0f2ee;
  --text-main: #17201d;
  --text-muted: #65706b;
  --border: #dce2dc;
  --blue: #2563eb;
  --green: #0f8f72;
  --red: #ef4444;
  --amber: #b7791f;
  --shadow-soft: 0 18px 45px rgba(18, 20, 21, 0.08);
  --shadow-tight: 0 8px 20px rgba(18, 20, 21, 0.06);
  --radius: 8px;
}

body.light {
  --sb-bg: #ffffff;
  --sb-hover: #edf2ee;
  --sb-text: #111815;
  --sb-muted: #5f6b66;
  --sb-border: #d9e0d9;
  --sb-soft: #f7f8f5;
  --sb-active-bg: rgba(15,143,114,0.12);
  --sb-active-text: #0f8f72;
  --main-bg: #ffffff;
  --card-bg: #f7f8f5;
  --input-bg: #eff2ee;
  --text-main: #111815;
  --text-muted: #5f6b66;
  --border: #d9e0d9;
}

body.dark {
  --sb-bg: #0f1213;
  --sb-hover: #1d2324;
  --sb-text: #eef2ef;
  --sb-muted: rgba(238,242,239,0.58);
  --sb-border: rgba(255,255,255,0.08);
  --sb-soft: rgba(255,255,255,0.04);
  --sb-active-bg: rgba(15,143,114,0.16);
  --sb-active-text: #9af0d5;
  --main-bg: #171b1c;
  --card-bg: #202526;
  --input-bg: #252b2c;
  --text-main: #eef2ef;
  --text-muted: #9aa6a1;
  --border: #323a3b;
  --shadow-soft: 0 18px 45px rgba(0, 0, 0, 0.24);
  --shadow-tight: 0 8px 20px rgba(0, 0, 0, 0.16);
}

/* --- Reset --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { background: var(--main-bg); }
body { font-family: 'Inter', sans-serif; background: var(--main-bg); color: var(--text-main); letter-spacing: 0; }
a { text-decoration: none; color: inherit; }
button { cursor: pointer; font-family: inherit; }
input, textarea { font-family: inherit; }

/* --- Layout --- */
.app-shell { display: flex; height: 100vh; width: 100vw; overflow: hidden; position: fixed; top: 0; left: 0; }
.sidebar { width: 276px; min-width: 276px; background: var(--sb-bg); display: flex; flex-direction: column; padding: 0.85rem 0.7rem; gap: 0.35rem; border-right: 1px solid var(--sb-border); height: 100%; }
.main { flex: 1; min-width: 0; position: relative; display: flex; flex-direction: column; overflow: hidden; background: var(--main-bg); height: 100%; }

/* --- Sidebar elements --- */
.sb-btn-new {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.72rem 0.85rem; border-radius: var(--radius);
  border: 1px solid var(--sb-border); background: var(--sb-soft);
  color: var(--sb-text); font-size: 0.88rem; font-weight: 650;
  transition: background 0.15s, border-color 0.15s; margin-bottom: 0.55rem;
}
.sb-btn-new:hover { background: var(--sb-hover); border-color: var(--green); }

.sb-section-label {
  font-size: 0.68rem; font-weight: 800; color: var(--sb-muted);
  padding: 0.6rem 0.8rem 0.25rem; text-transform: uppercase; letter-spacing: 0.05em;
}

.sb-item {
  display: flex; align-items: center; gap: 10px;
  padding: 0.55rem 0.8rem; border-radius: var(--radius);
  font-size: 0.85rem; color: var(--sb-text);
  transition: background 0.15s; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.sb-item:hover { background: var(--sb-hover); }
.sb-item.active { background: var(--sb-active-bg); font-weight: 700; color: var(--sb-active-text); }
.sb-item svg { flex-shrink: 0; }

.sb-scroll { flex: 1; overflow-y: auto; padding-bottom: 1rem; }
.sb-footer { border-top: 1px solid var(--sb-border); padding-top: 0.75rem; margin-top: auto; }

/* --- Folder switch in sidebar --- */
.folder-switch-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.5rem 0.8rem; border-radius: var(--radius);
  transition: background 0.15s;
}
.folder-switch-row:hover { background: var(--sb-hover); }
.folder-switch-row .label { font-size: 0.83rem; color: var(--sb-text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; flex:1; }
.folder-switch-row .sublabel { font-size: 0.68rem; color: var(--text-muted); }

/* Toggle switch */
.toggle { position: relative; width: 32px; height: 18px; flex-shrink: 0; }
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-track {
  position: absolute; inset: 0; border-radius: 18px;
  background: var(--border); transition: background 0.2s; cursor: pointer;
}
.toggle input:checked + .toggle-track { background: var(--green); }
.toggle-track::after {
  content: ''; position: absolute; top: 2px; left: 2px;
  width: 14px; height: 14px; border-radius: 50%;
  background: white; transition: transform 0.2s;
}
.toggle input:checked + .toggle-track::after { transform: translateX(14px); }

/* --- Top nav --- */
.top-nav {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: 0.85rem 1.5rem; border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--main-bg) 92%, transparent); backdrop-filter: blur(12px);
}
.mode-selector { display: flex; background: var(--input-bg); padding: 3px; border-radius: 10px; gap: 3px; border: 1px solid var(--border); }
.mode-btn {
  padding: 6px 14px; border-radius: 7px; font-size: 0.82rem; font-weight: 700;
  border: none; color: var(--text-muted); background: transparent; transition: all 0.2s;
}
.mode-btn.active { background: var(--card-bg); color: var(--text-main); box-shadow: var(--shadow-tight); }

.btn-icon {
  width: 34px; height: 34px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--card-bg); color: var(--text-main);
  display: flex; align-items: center; justify-content: center; transition: background 0.15s;
}
.btn-icon:hover { background: var(--input-bg); }

/* --- Buttons --- */
.btn-primary {
  background: var(--blue); color: white; border: none;
  padding: 0.7rem 1.2rem; border-radius: var(--radius);
  font-weight: 600; font-size: 0.88rem; transition: opacity 0.2s;
}
.btn-primary:hover { opacity: 0.88; }
.btn-primary:disabled { opacity: 0.4; cursor: default; }

.btn-danger {
  background: transparent; color: var(--red);
  border: 1px solid var(--red); padding: 0.6rem 1rem;
  border-radius: var(--radius); font-weight: 600; font-size: 0.85rem; transition: all 0.2s;
}
.btn-danger:hover { background: var(--red); color: white; }

.btn-outline {
  background: transparent; color: var(--text-main);
  border: 1px solid var(--border); padding: 0.65rem 1rem;
  border-radius: var(--radius); font-weight: 600; font-size: 0.85rem; transition: all 0.15s;
}
.btn-outline:hover { border-color: var(--blue); color: var(--blue); }
.sidebar .btn-outline { color: var(--sb-text); border-color: var(--sb-border); background: var(--sb-soft); }
.sidebar .btn-outline:hover { color: var(--sb-active-text); border-color: var(--green); }

/* --- Toast --- */
#toast-container { position: fixed; bottom: 1.5rem; right: 1.5rem; z-index: 9999; display: flex; flex-direction: column; gap: 0.5rem; }
.toast {
  background: var(--card-bg); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 0.8rem 1.2rem;
  font-size: 0.88rem; font-weight: 500;
  box-shadow: var(--shadow-soft);
  display: flex; align-items: center; gap: 10px;
  animation: slideIn 0.3s ease;
  max-width: 320px;
}
.toast.success { border-left: 3px solid var(--green); }
.toast.error   { border-left: 3px solid var(--red); }
.toast.info    { border-left: 3px solid var(--blue); }
@keyframes slideIn { from { opacity:0; transform: translateY(10px); } to { opacity:1; transform: translateY(0); } }

/* --- Scrollbars --- */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

@media (max-width: 860px) {
  .app-shell { flex-direction: column; }
  .sidebar {
    width: 100%; min-width: 0; height: auto; max-height: 42vh;
    border-right: 0; border-bottom: 1px solid var(--sb-border);
  }
  .sb-btn-new { margin-bottom: 0.25rem; }
  .sb-scroll { min-height: 0; }
  .sb-footer { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
  .main { height: 58vh; min-height: 420px; }
  .top-nav { padding: 0.75rem; align-items: stretch; flex-direction: column; }
  .mode-selector { width: 100%; }
  .mode-btn { flex: 1; }
}

@media (max-width: 520px) {
  .sidebar { max-height: 38vh; padding: 0.65rem; }
  .main { height: 62vh; min-height: 380px; }
  .sb-footer { grid-template-columns: 1fr; }
  .top-nav { gap: 0.65rem; }
  #toast-container { left: 1rem; right: 1rem; bottom: 1rem; }
  .toast { max-width: none; }
}