* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  background: var(--c-bg-0);
  color: var(--c-text-0);
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-shell {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: var(--space-6);
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}

.app-header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--fs-lg);
  font-weight: var(--fw-semibold);
  letter-spacing: -0.01em;
}

.app-header__brand-mark {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--c-accent), #8a5bff);
  display: grid;
  place-items: center;
  color: white;
  font-weight: var(--fw-bold);
  font-size: var(--fs-sm);
  letter-spacing: 0.04em;
}

.app-header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.screen { display: none; }
.screen[data-active="true"] { display: block; animation: fade-in var(--motion-base) var(--easing-standard); }

@keyframes fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.stack { display: flex; flex-direction: column; gap: var(--space-4); }
.stack-sm { display: flex; flex-direction: column; gap: var(--space-2); }
.row { display: flex; align-items: center; gap: var(--space-3); }
.row-end { justify-content: flex-end; }
.row-between { justify-content: space-between; }
.spacer { flex: 1; }

.card {
  background: var(--c-bg-1);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-md);
}

.interview-layout {
  background: var(--c-bg-1);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-xl);
  display: flex;
  flex-direction: column;
  height: clamp(560px, 78vh, 880px);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.interview-layout__topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-6);
  background: var(--c-bg-elev);
  border-bottom: 1px solid var(--c-border);
}

.interview-layout__chat {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  scroll-behavior: smooth;
}

.interview-layout__composer {
  border-top: 1px solid var(--c-border);
  background: var(--c-bg-elev);
  padding: var(--space-4) var(--space-5);
}

@media (max-width: 640px) {
  .app-shell { padding: var(--space-3); gap: var(--space-3); }
  .card { padding: var(--space-5); }
  .interview-layout { height: calc(100vh - var(--space-3) * 4 - 56px); border-radius: var(--radius-lg); }
  .interview-layout__chat { padding: var(--space-4); }
  .interview-layout__composer { padding: var(--space-3); }
  .app-header__brand { font-size: var(--fs-md); }
}