/* =========================================================================
   Atelier AI — Layout & Responsive
   Owns: header, main shell, left/right panels, footer, breakpoints
   ========================================================================= */

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  /* 给 fixed footer 预留空间，避免遮挡最底部内容 */
  padding-bottom: var(--footer-h);
  box-sizing: border-box;
}

/* =========================================================================
   Header — sticky, translucent on scroll
   ========================================================================= */
header,
.app-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-5);
  border-bottom: 1px solid transparent;
  background: color-mix(in srgb, var(--bg-canvas) 85%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  transition: border-color var(--duration-fast) var(--ease-out),
              box-shadow var(--duration-fast) var(--ease-out);
  flex-shrink: 0;
}
header.is-scrolled,
.app-header.is-scrolled {
  border-bottom-color: var(--border-subtle);
  box-shadow: var(--shadow-xs);
}

/* Brand cluster (logo + name) */
.app-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}
.app-logo {
  width: 28px;
  height: 28px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-gradient);
  padding: 1px;
  box-shadow: var(--shadow-sm);
}
.app-logo > img,
.app-logo > svg {
  width: 100%;
  height: 100%;
  border-radius: calc(var(--radius-md) - 2px);
  background: var(--bg-elevated);
  padding: 3px;
  box-sizing: border-box;
}
.app-name {
  font-size: var(--text-lg);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-tight);
  margin: 0;
  display: inline-flex;
  align-items: baseline;
  gap: var(--space-1-5);
}
.app-version {
  font-size: var(--text-xs);
  font-weight: var(--weight-medium);
  padding: 2px 6px;
  border-radius: var(--radius-full);
  background: var(--accent-gradient-soft);
  color: var(--accent-secondary);
  letter-spacing: var(--tracking-normal);
}

/* Header nav (tabs) */
.app-nav {
  flex: 1;
  display: flex;
  gap: var(--space-0-5);
  align-items: center;
  min-width: 0;
}

/* Header actions (theme toggle, drawer toggle on narrow) */
.app-actions {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-shrink: 0;
}

/* =========================================================================
   Main shell
   ========================================================================= */
main,
.app-main {
  flex: 1;
  display: flex;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  max-width: 1680px;
  width: 100%;
  margin: 0 auto;
  box-sizing: border-box;
  min-height: 0;
}

#left-panel,
.left-panel {
  flex: 1 1 0%;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
}

#right-panel,
.right-panel {
  width: 440px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-width: 0;
  /* Keep task list visible while scrolling long forms */
  position: sticky;
  top: calc(var(--header-h) + var(--space-4));
  /* 视口高 - header - 上下 padding - footer */
  max-height: calc(100vh - var(--header-h) - var(--space-4) - var(--space-4) - var(--footer-h));
  overflow: auto;
}

/* =========================================================================
   Footer status bar
   ========================================================================= */
footer,
.app-footer {
  /* 始终固定在视口底部；body 通过 padding-bottom 预留空间 */
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding: var(--space-1-5) var(--space-5);
  border-top: 1px solid var(--border-subtle);
  background: color-mix(in srgb, var(--bg-canvas) 90%, transparent);
  backdrop-filter: saturate(1.4) blur(12px);
  -webkit-backdrop-filter: saturate(1.4) blur(12px);
  font-size: var(--text-sm);
  color: var(--text-secondary);
}
.app-footer .status-left,
.app-footer .status-right {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}

/* =========================================================================
   Mode panels — exclusive display
   ========================================================================= */
.mode-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

/* =========================================================================
   Breakpoints
   ========================================================================= */

/* ≥1280px — default wide */

/* 1024 ~ 1279 : compact double column */
@media (max-width: 1279px) {
  main,
  .app-main {
    padding: var(--space-4);
    gap: var(--space-3);
  }
  #right-panel,
  .right-panel {
    width: 380px;
  }
  .tab {
    padding: 8px 10px;
    font-size: var(--text-sm);
  }
}

/* <1024 : collapse right panel into drawer */
@media (max-width: 1023px) {
  main,
  .app-main {
    flex-direction: column;
    padding: var(--space-3);
  }
  #right-panel,
  .right-panel {
    position: fixed;
    top: 0;
    right: 0;
    bottom: var(--footer-h); /* 避让 fixed footer */
    width: min(420px, 92vw);
    max-height: calc(100vh - var(--footer-h));
    background: var(--bg-elevated);
    box-shadow: var(--shadow-xl);
    border-left: 1px solid var(--border-default);
    padding: var(--space-4);
    z-index: var(--z-dropdown);
    transform: translateX(100%);
    transition: transform var(--duration-normal) var(--ease-out);
  }
  body[data-drawer="open"] #right-panel,
  body[data-drawer="open"] .right-panel {
    transform: translateX(0);
  }
  body[data-drawer="open"]::after {
    content: "";
    position: fixed;
    inset: 0;
    background: var(--bg-overlay);
    z-index: calc(var(--z-dropdown) - 1);
    animation: overlay-in var(--duration-normal) var(--ease-out);
  }
  .drawer-toggle {
    display: inline-flex !important;
  }
}

/* <768 : minimal (tablet portrait / mobile) */
@media (max-width: 767px) {
  header,
  .app-header {
    padding: var(--space-2) var(--space-3);
    gap: var(--space-2);
  }
  .app-nav {
    overflow-x: auto;
    overflow-y: hidden;
    scrollbar-width: none;
    -ms-overflow-style: none;
  }
  .app-nav::-webkit-scrollbar { display: none; }
  .app-name        { font-size: var(--text-md); }
  .app-version     { display: none; }
  main,
  .app-main {
    padding: var(--space-3) var(--space-2);
    gap: var(--space-2);
  }
  .form-row        { flex-direction: column; align-items: stretch; }
  .form-row > label { width: auto; }
  .modal-dialog    { border-radius: var(--radius-lg); padding: var(--space-4); }
  .card            { padding: var(--space-3); }
  .tab             { padding: 6px 8px; }
  .tab .tab-label  { display: none; }  /* icons only */
  .tab.active::after { left: 6px; right: 6px; }
  footer,
  .app-footer {
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
  }
}

/* Drawer toggle is hidden on wide screens */
.drawer-toggle { display: none; }