/* ====== Base Reset ====== */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

html, body {
  height: 100%;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
}

/* ====== App Shell ====== */
.app-shell {
  max-width: 480px;
  margin: 0 auto;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--color-surface);
  border-left: 1px solid var(--color-border-mid);
  border-right: 1px solid var(--color-border-mid);
}

/* ====== Header ====== */
header {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  padding: 0.75rem 1rem;
  background: linear-gradient(90deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  box-shadow: var(--shadow-header);
}

header h1 {
  flex: 1;
  font-size: 1.05rem;
  text-align: center;
  font-weight: 600;
}

.header-btn {
  background: transparent;
  border: none;
  color: var(--color-bg);
  font-size: 0.9rem;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
}

.header-btn.invisible {
  visibility: hidden;
}

/* ====== Brand Bar ====== */
.brand-bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 1rem;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

.brand-logo {
  width: 40px;
  height: auto;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.brand-name {
  font-weight: 700;
  letter-spacing: 0.08em;
  font-size: 0.9rem;
}

.brand-tagline {
  font-size: 0.72rem;
  color: var(--color-text-secondary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ====== Main / Screen Layout ====== */
main {
  flex: 1;
  padding: 0.45rem 0 0;
}

.screen {
  display: none;
}

.screen:not(#homeScreen):not(#getInfoScreen) {
  padding: 0 1rem 1.5rem;
}

#getInfoScreen .section-description {
  padding: 0 1rem;
  margin-bottom: 0.75rem;
}

.screen.active {
  display: block;
}

/* ====== Text & Sections ====== */
.section-title {
  font-weight: 600;
  font-size: 0.98rem;
  margin-bottom: 0.45rem;
  margin-top: 0.5rem;
}

.section-description {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

/* ====== Footer Note ====== */
.footer-note {
  font-size: 0.74rem;
  color: var(--color-text-muted);
  text-align: center;
  padding: 0.7rem 0.9rem 0.9rem;
  background: var(--color-surface-muted);
  border-top: 1px solid var(--color-border);
}

/* ====== Responsive Tuning ====== */
@media (max-width: 420px) {
  header h1 {
    font-size: 1.02rem;
  }

  .section-title {
    font-size: 0.96rem;
  }

  .section-description {
    font-size: 0.83rem;
  }
}

@media (max-width: 380px) {
  header h1 {
    font-size: 0.98rem;
  }
}