/*
  App shell & primitives — Notion-style, responsive. Mobile = bottom tab bar;
  desktop (>=900px) = left sidebar + wide content. Token-only (Rule 5).
*/
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg-app);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  -webkit-tap-highlight-color: transparent;
}

/* --- App shell ------------------------------------------------------------ */
.app-shell {
  min-height: 100vh; min-height: 100dvh;
  max-width: var(--content-max-width); margin: 0 auto;
  display: flex; flex-direction: column; background: var(--color-bg-app);
}

/* --- Header (page title) -------------------------------------------------- */
.app-bar {
  position: sticky; top: 0; z-index: 20;
  display: flex; flex-direction: column; gap: 2px;
  padding: calc(var(--safe-top) + var(--space-3)) var(--space-4) var(--space-3);
  background: var(--color-bar);
  -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur);
  border-bottom: 1px solid var(--color-bar-border);
}
.app-bar__head { display: flex; align-items: center; justify-content: space-between; gap: var(--space-4); }
.app-bar__title { margin: 0; min-width: 0; font-size: var(--text-xl); font-weight: var(--weight-bold); letter-spacing: -0.01em; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.app-bar__sub { margin: 0; font-size: var(--text-sm); color: var(--color-text-muted); }
.app-bar__actions { display: flex; align-items: center; gap: var(--space-4); flex: 0 0 auto; }
.app-bar__actions a, .app-bar__actions .add-link { color: var(--color-text-muted); white-space: nowrap; }
.app-bar__actions a:hover { color: var(--color-text); }

/* --- Main ----------------------------------------------------------------- */
.app-main {
  flex: 1; padding: var(--space-4);
  /* Clear both the global ask-bar and the bottom tab-bar. */
  padding-bottom: calc(var(--tabbar-height) + var(--askbar-height) + var(--safe-bottom) + var(--space-8));
}

/* --- Card ----------------------------------------------------------------- */
.card { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg); padding: var(--space-4); }

/* --- Empty state ---------------------------------------------------------- */
.placeholder { display: flex; flex-direction: column; align-items: center; text-align: center; gap: var(--space-3); padding: var(--space-10) var(--space-5); color: var(--color-text-muted); }
.placeholder__icon { display: grid; place-items: center; width: 56px; height: 56px; border-radius: var(--radius-full); background: var(--color-primary-soft); color: var(--color-primary); }
.placeholder__icon svg { width: 26px; height: 26px; }
.placeholder h2 { margin: 0; font-size: var(--text-lg); font-weight: var(--weight-semibold); color: var(--color-text); }
.placeholder p { margin: 0; max-width: 36ch; font-size: var(--text-base); line-height: 1.5; }
.placeholder__tag { margin-top: var(--space-2); font-size: var(--text-xs); font-weight: var(--weight-semibold); text-transform: uppercase; letter-spacing: 0.06em; color: var(--color-text-faint); }

/* --- Chips ---------------------------------------------------------------- */
.chip { display: inline-flex; align-items: center; gap: var(--space-1); padding: 2px var(--space-2); border-radius: var(--radius-sm); font-size: var(--text-xs); font-weight: var(--weight-medium); background: var(--color-surface-alt); color: var(--color-text-muted); white-space: nowrap; }
a.chip { text-decoration: none; }
a.chip:hover { background: var(--color-hover); }

/* --- Buttons (Notion) ----------------------------------------------------- */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: var(--space-2); min-height: 34px; padding: var(--space-2) var(--space-4); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); color: var(--color-text); font-size: var(--text-sm); font-weight: var(--weight-medium); font-family: inherit; cursor: pointer; text-decoration: none; transition: background 0.12s ease; }
.btn:hover { background: var(--color-hover); }
.btn--primary { background: var(--color-btn); border-color: var(--color-btn); color: var(--color-on-btn); }
.btn--primary:hover { background: var(--color-btn-hover); border-color: var(--color-btn-hover); }
.btn--danger { background: var(--color-danger); border-color: var(--color-danger); color: #fff; }
.btn--ghost { background: transparent; border-color: transparent; color: var(--color-text-muted); min-height: auto; padding: var(--space-1) var(--space-2); }
.btn--block { width: 100%; }
.btn--sm { min-height: 30px; padding: var(--space-1) var(--space-3); font-size: var(--text-sm); }

/* --- Floating compose (mobile) -------------------------------------------- */
.fab { position: fixed; right: max(var(--space-4), calc((100vw - var(--content-max-width)) / 2 + var(--space-4))); bottom: calc(var(--tabbar-height) + var(--askbar-height) + var(--safe-bottom) + var(--space-3)); z-index: 30; display: grid; place-items: center; width: 48px; height: 48px; border-radius: var(--radius-full); background: var(--color-primary); color: var(--color-on-primary); border: 1px solid var(--color-border); text-decoration: none; box-shadow: var(--shadow-up); }
.fab:active { opacity: 0.8; }
.fab svg { width: 26px; height: 26px; }

/* --- Navigation: bottom tab bar (mobile) ---------------------------------- */
.nav-brand { display: none; }
.nav-collapse { display: none; }  /* desktop-only sidebar collapse toggle */
.tab-bar { position: fixed; bottom: 0; left: 0; right: 0; z-index: 25; display: grid; grid-auto-flow: column; grid-auto-columns: 1fr; max-width: var(--content-max-width); margin: 0 auto; height: calc(var(--tabbar-height) + var(--safe-bottom)); padding-bottom: var(--safe-bottom); background: var(--color-bar); -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur); border-top: 1px solid var(--color-bar-border); }
.tab-item { display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 2px; text-decoration: none; color: var(--color-text-faint); font-size: 10px; font-weight: var(--weight-medium); min-width: 0; }
.tab-item span { max-width: 100%; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.tab-item svg { width: 24px; height: 24px; }
.tab-item.is-active { color: var(--color-primary); }

/* --- Global assistant bar (fixed, every page) ----------------------------- */
.global-ask {
  position: fixed; left: 0; right: 0; z-index: 24;
  bottom: calc(var(--tabbar-height) + var(--safe-bottom));
  max-width: var(--content-max-width); margin: 0 auto;
  display: flex; align-items: center; gap: var(--space-2);
  height: var(--askbar-height); padding: 0 var(--space-3);
  background: var(--color-bar);
  -webkit-backdrop-filter: var(--blur); backdrop-filter: var(--blur);
  border-top: 1px solid var(--color-bar-border);
}
.global-ask__input {
  flex: 1; min-width: 0; height: 38px;
  padding: 0 var(--space-3);
  border: 1px solid var(--color-border); border-radius: var(--radius-full);
  background: var(--color-surface); color: var(--color-text);
  font-family: inherit; font-size: var(--text-base);
}
.global-ask__input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 2px var(--color-primary-soft); }
.global-ask__model {
  flex: 0 0 auto; max-width: 8.5rem; height: 38px;
  padding: 0 var(--space-2); border: 1px solid var(--color-border);
  border-radius: var(--radius-md); background: var(--color-surface);
  color: var(--color-text-muted); font-family: inherit; font-size: var(--text-sm);
}
.global-ask__send {
  flex: 0 0 auto; display: grid; place-items: center; width: 38px; height: 38px;
  border: none; border-radius: var(--radius-full);
  background: var(--color-btn); color: var(--color-on-btn); cursor: pointer;
}
.global-ask__send svg { width: 18px; height: 18px; }
.global-ask__send:hover { background: var(--color-btn-hover); }
.global-ask__improve {
  flex: 0 0 auto; display: grid; place-items: center; width: 38px; height: 38px;
  border: 1px solid var(--color-border); border-radius: var(--radius-full);
  background: var(--color-surface); color: var(--color-text-muted); cursor: pointer;
}
.global-ask__improve svg { width: 17px; height: 17px; }
.global-ask__improve:hover { background: var(--color-hover); color: var(--color-text); }
.global-ask__improve:disabled { opacity: 0.5; cursor: default; }

/* --- Auth / login --------------------------------------------------------- */
/* Login has no sidebar/tab-bar: strip the shell's nav offset + padding so the
   card centres in the full viewport (both axes), not pushed right/down. */
.app-main:has(.auth) { padding: 0; }
.auth { flex: 1; display: flex; flex-direction: column; justify-content: center; gap: var(--space-6); padding: var(--space-6); min-height: 100dvh; max-width: 380px; margin: 0 auto; width: 100%; }
.auth__brand { text-align: center; font-size: var(--text-2xl); font-weight: var(--weight-bold); letter-spacing: -0.01em; color: var(--color-text); }
.auth__brand span { display: block; margin-top: var(--space-2); font-size: var(--text-base); font-weight: var(--weight-regular); color: var(--color-text-muted); letter-spacing: 0; }
.auth__card { display: flex; flex-direction: column; gap: var(--space-4); }
.field { display: flex; flex-direction: column; gap: var(--space-2); }
.field label { font-size: var(--text-sm); font-weight: var(--weight-semibold); color: var(--color-text-muted); }
.field input { width: 100%; padding: var(--space-3) var(--space-4); border: 1px solid var(--color-border); border-radius: var(--radius-md); font-size: var(--text-base); font-family: inherit; background: var(--color-surface); color: var(--color-text); }
.field input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 2px var(--color-primary-soft); }
.auth__error { margin: 0; padding: var(--space-3); border-radius: var(--radius-md); background: var(--color-danger-soft); color: var(--color-danger); font-size: var(--text-sm); }

.icon-defs { position: absolute; width: 0; height: 0; overflow: hidden; }

/* ========================================================================== */
/*  DESKTOP (>= 900px): Notion-style left sidebar + wide content              */
/* ========================================================================== */
@media (min-width: 900px) {
  .app-shell { max-width: none; margin: 0; margin-left: var(--sidebar-width); }
  /* No sidebar on the login screen → don't reserve its width. */
  .app-shell:has(.auth) { margin-left: 0; }
  .app-main:has(.auth) { padding: 0; max-width: none; }

  .nav-brand { display: flex; align-items: center; gap: var(--space-2); padding: var(--space-2) var(--space-3) var(--space-4); font-size: var(--text-base); font-weight: var(--weight-bold); color: var(--color-text); text-decoration: none; }

  .tab-bar {
    position: fixed; top: 0; left: 0; bottom: 0; right: auto;
    width: var(--sidebar-width); height: 100%; max-width: none; margin: 0;
    display: flex; flex-direction: column; align-items: stretch; gap: 1px;
    padding: var(--space-4) var(--space-2); overflow-y: auto;
    background: var(--color-sidebar);
    border-top: none; border-right: 1px solid var(--color-border);
    -webkit-backdrop-filter: none; backdrop-filter: none;
  }
  .tab-item { flex-direction: row; justify-content: flex-start; gap: var(--space-3); padding: var(--space-2) var(--space-3); border-radius: var(--radius-md); font-size: var(--text-sm); font-weight: var(--weight-medium); color: var(--color-text-muted); }
  .tab-item svg { width: 20px; height: 20px; }
  .tab-item:hover { background: var(--color-hover); }
  .tab-item.is-active { background: var(--color-hover); color: var(--color-text); }

  .app-bar { position: sticky; top: 0; background: var(--color-bar); border-bottom: 1px solid var(--color-bar-border); padding: var(--space-5) var(--space-10) var(--space-3); max-width: var(--content-max-width); margin: 0 auto; }
  .app-bar__title { font-size: var(--text-2xl); }

  .app-main { max-width: var(--content-max-width); margin: 0 auto; width: 100%; padding: var(--space-6) var(--space-10) calc(var(--askbar-height) + var(--space-10)); }

  .fab { display: none; }

  /* Global ask-bar: pinned to the bottom of the content column, offset past the sidebar. */
  .global-ask {
    left: var(--sidebar-width); right: 0; bottom: 0;
    max-width: var(--content-max-width); margin: 0 auto;
    padding: 0 var(--space-10);
    border-top: 1px solid var(--color-border);
  }
  .nav-collapsed .global-ask { left: 72px; }

  /* Collapsible sidebar */
  .nav-collapse { display: inline-grid; place-items: center; width: 34px; height: 34px; margin: 0 var(--space-2) var(--space-3); border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-surface); color: var(--color-text-muted); cursor: pointer; }
  .nav-collapse:hover { background: var(--color-hover); color: var(--color-text); }
  .nav-collapse svg { width: 18px; height: 18px; transition: transform 0.15s ease; }
  .nav-collapsed .nav-collapse svg { transform: rotate(180deg); }
  .nav-collapsed .tab-bar { width: 72px; padding: var(--space-4) var(--space-2); }
  .nav-collapsed .app-shell { margin-left: 72px; }
  .nav-collapsed .nav-brand { display: none; }
  .nav-collapsed .tab-item { justify-content: center; padding: var(--space-2); }
  .nav-collapsed .tab-item span { display: none; }
}