/* ===== Variables — Microsoft Fluent Design ===== */
:root {
  --c-bg: #f5f5f5;
  --c-surface: #ffffff;
  --c-border: #e0e0e0;
  --c-text: #242424;
  --c-text-secondary: #616161;
  --c-primary: #0078d4;
  --c-primary-hover: #106ebe;
  --c-primary-bg: #deecf9;
  --c-success: #107c10;
  --c-success-bg: #dff6dd;
  --c-warning: #ca5010;
  --c-warning-bg: #fff4ce;
  --c-danger: #d13438;
  --c-danger-bg: #fde7e9;
  --c-sidebar-bg: #fafafa;
  --c-code-bg: #1b1a19;
  --c-code-text: #f3f2f1;
  --radius: 4px;
  --radius-lg: 8px;
  --shadow: 0 2px 4px rgba(0,0,0,.04), 0 0 2px rgba(0,0,0,.06);
  --shadow-lg: 0 8px 16px rgba(0,0,0,.08), 0 0 2px rgba(0,0,0,.06);
  --sidebar-width: 260px;
  --header-height: 48px;
  --transition: .15s ease;
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: "Segoe UI", "Segoe UI Web", "Noto Sans SC", -apple-system, BlinkMacSystemFont, Helvetica, Arial, sans-serif;
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.5;
  min-height: 100vh;
}

/* ===== Header ===== */
.app-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--header-height);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 20px;
  background: #0078d4;
  color: #ffffff;
  box-shadow: 0 1px 2px rgba(0,0,0,.12);
}
.app-title {
  font-size: 1rem; font-weight: 600;
  color: #ffffff;
  background: none;
  -webkit-background-clip: unset; -webkit-text-fill-color: unset;
  background-clip: unset;
}
.lang-switcher {
  padding: 4px 10px; border-radius: var(--radius);
  border: 1px solid rgba(255,255,255,.4); background: rgba(255,255,255,.15);
  font-size: .85rem; cursor: pointer; color: #ffffff;
  outline: none;
}
.lang-switcher option { color: var(--c-text); background: var(--c-surface); }

/* ===== Layout ===== */
.app-container {
  display: flex;
  margin-top: var(--header-height);
  min-height: calc(100vh - var(--header-height));
}

/* ===== Sidebar ===== */
.sidebar {
  position: fixed; top: var(--header-height); left: 0; bottom: 0;
  width: var(--sidebar-width);
  background: var(--c-surface);
  border-right: 1px solid var(--c-border);
  padding: 16px 12px;
  overflow-y: auto;
  display: flex; flex-direction: column;
  transition: transform var(--transition);
  z-index: 50;
}
.step-list { list-style: none; flex: 1; }
.step-item {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 10px 12px; margin-bottom: 4px;
  border-radius: var(--radius);
  cursor: pointer; font-size: .9rem;
  transition: background var(--transition);
}
.step-item:hover { background: rgba(0,0,0,.03); }
.step-item.active {
  background: var(--c-primary-bg); color: var(--c-primary); font-weight: 600;
  border-left: 3px solid var(--c-primary);
  padding-left: 9px;
}
.step-item.done { color: var(--c-success); }
.step-item.done .step-number { background: var(--c-success); color: #fff; }
.step-number {
  flex-shrink: 0;
  width: 26px; height: 26px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: .75rem; font-weight: 700;
  background: var(--c-border); color: var(--c-text-secondary);
  transition: background var(--transition), color var(--transition);
}
.step-item.active .step-number { background: var(--c-primary); color: #fff; }
.step-label { padding-top: 2px; }
.btn-reset {
  margin-top: 16px; font-size: .85rem;
  width: 100%; padding: 8px 12px;
  border: 1px solid var(--c-danger); border-radius: var(--radius);
  background: transparent; color: var(--c-danger);
  cursor: pointer; font-weight: 700;
  transition: background var(--transition), color var(--transition);
}
.btn-reset:hover { background: var(--c-danger); color: #fff; }

/* ===== Main Content ===== */
.main-content {
  flex: 1; margin-left: var(--sidebar-width);
  padding: 32px 40px;
  max-width: 820px;
}

/* ===== Screen: Welcome ===== */
.welcome-hero { text-align: center; margin-bottom: 40px; }
.welcome-icon { font-size: 4rem; margin-bottom: 12px; }
.welcome-hero h2 { font-size: 1.8rem; margin-bottom: 8px; }
.welcome-subtitle { color: var(--c-text-secondary); font-size: 1.1rem; margin-bottom: 16px; }
.welcome-intro {
  max-width: 560px; margin: 0 auto;
  color: var(--c-text-secondary); font-size: .95rem; line-height: 1.7;
}
.welcome-options { max-width: 520px; margin: 0 auto; }
.option-group { margin-bottom: 28px; }
.option-group > label { display: block; font-weight: 600; margin-bottom: 12px; font-size: 1rem; }
.option-cards { display: flex; gap: 12px; flex-wrap: wrap; }
.option-card {
  flex: 1; min-width: 120px;
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  padding: 16px 12px;
  border: 2px solid var(--c-border); border-radius: var(--radius-lg);
  background: var(--c-surface); cursor: pointer;
  font-size: .95rem; font-weight: 500;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.option-card:hover { border-color: var(--c-primary); box-shadow: var(--shadow); }
.option-card.selected { border-color: var(--c-primary); background: var(--c-primary-bg); }
.option-icon { font-size: 1.8rem; }
.option-label { font-size: .9rem; }
.btn-lg { width: 100%; padding: 14px; font-size: 1.05rem; margin-top: 12px; }

/* ===== Screen: Step ===== */
.step-header { margin-bottom: 24px; display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.step-badge {
  background: var(--c-primary); color: #fff;
  font-size: .8rem; font-weight: 700;
  padding: 4px 12px; border-radius: 20px;
}
.step-title { font-size: 1.4rem; }
.step-optional {
  font-size: .85rem; color: var(--c-text-secondary);
  background: var(--c-warning-bg); padding: 2px 10px; border-radius: 12px;
}
.step-body { margin-bottom: 32px; }
.step-body p { margin-bottom: 12px; line-height: 1.7; }
.step-body h3 { margin: 24px 0 12px; font-size: 1.1rem; }
.step-body ul, .step-body ol { margin: 8px 0 16px 20px; }
.step-body li { margin-bottom: 6px; line-height: 1.6; }

/* Command blocks */
.command-block {
  position: relative;
  background: var(--c-code-bg); color: var(--c-code-text);
  border-radius: var(--radius);
  padding: 14px 16px; margin: 12px 0;
  font-family: "Cascadia Code", "Fira Code", Consolas, monospace;
  font-size: .9rem; line-height: 1.5;
  overflow-x: auto;
}
.command-block code { color: inherit; }
.btn-copy {
  position: absolute; top: 8px; right: 8px;
  background: rgba(255,255,255,.15); color: var(--c-code-text);
  border: none; border-radius: 6px;
  padding: 4px 10px; font-size: .75rem;
  cursor: pointer; transition: background var(--transition);
}
.btn-copy:hover { background: rgba(255,255,255,.25); }
.btn-copy.copied { background: var(--c-success); color: #fff; }

/* Info/warning/tip boxes */
.info-box {
  border-radius: var(--radius);
  padding: 14px 16px; margin: 16px 0;
  font-size: .9rem; line-height: 1.6;
  display: flex; gap: 10px;
}
.info-box.info { background: var(--c-primary-bg); border-left: 4px solid var(--c-primary); }
.info-box.success { background: var(--c-success-bg); border-left: 4px solid var(--c-success); }
.info-box.warning { background: var(--c-warning-bg); border-left: 4px solid var(--c-warning); }
.info-box.danger { background: var(--c-danger-bg); border-left: 4px solid var(--c-danger); }
.info-box-icon { flex-shrink: 0; font-size: 1.1rem; }
.info-box-text { flex: 1; }

/* Substeps */
.substep {
  border: 1px solid var(--c-border); border-radius: var(--radius);
  padding: 16px 20px; margin: 16px 0;
  background: var(--c-surface);
}
.substep-header { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.substep-number {
  width: 24px; height: 24px; border-radius: 50%;
  background: var(--c-primary-bg); color: var(--c-primary);
  display: flex; align-items: center; justify-content: center;
  font-size: .75rem; font-weight: 700; flex-shrink: 0;
}
.substep-title { font-weight: 600; }
.substep-body { padding-left: 34px; }
.substep-why {
  margin-top: 8px; padding: 8px 12px;
  background: var(--c-bg); border-radius: 6px;
  font-size: .85rem; color: var(--c-text-secondary);
  cursor: pointer;
}
.substep-why summary { font-weight: 600; color: var(--c-primary); }

/* Account type cards */
.account-cards { display: flex; gap: 16px; margin: 16px 0; flex-wrap: wrap; }
.account-card {
  flex: 1; min-width: 200px;
  border: 2px solid var(--c-border); border-radius: var(--radius-lg);
  padding: 20px; cursor: pointer;
  transition: border-color var(--transition), box-shadow var(--transition);
  background: var(--c-surface);
}
.account-card:hover { border-color: var(--c-primary); box-shadow: var(--shadow); }
.account-card.selected { border-color: var(--c-primary); background: var(--c-primary-bg); }
.account-card-title { font-weight: 600; font-size: 1.05rem; margin-bottom: 6px; }
.account-card-desc { font-size: .85rem; color: var(--c-text-secondary); }

/* ===== FAQ Accordion ===== */
.faq-section { border-top: 1px solid var(--c-border); padding-top: 24px; margin-top: 32px; }
.faq-section h3 { margin-bottom: 16px; font-size: 1.1rem; }
.accordion-item {
  border: 1px solid var(--c-border); border-radius: var(--radius);
  margin-bottom: 8px; overflow: hidden; background: var(--c-surface);
}
.accordion-trigger {
  width: 100%; background: none; border: none;
  padding: 14px 16px; font-size: .95rem;
  text-align: left; cursor: pointer;
  display: flex; align-items: center; justify-content: space-between;
  font-weight: 500; color: var(--c-text);
  transition: background var(--transition);
}
.accordion-trigger:hover { background: var(--c-bg); }
.accordion-arrow {
  transition: transform var(--transition); font-size: .8rem;
}
.accordion-item.open .accordion-arrow { transform: rotate(180deg); }
.accordion-body {
  max-height: 0; overflow: hidden;
  transition: max-height .3s ease;
}
.accordion-item.open .accordion-body { max-height: 800px; }
.accordion-body-inner {
  padding: 0 16px 16px;
  font-size: .9rem; color: var(--c-text-secondary); line-height: 1.7;
}

/* ===== Step Actions ===== */
.step-actions {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: 24px; border-top: 1px solid var(--c-border);
  margin-top: 16px; gap: 12px;
}
.step-actions-right { display: flex; gap: 10px; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 10px 20px; border-radius: var(--radius);
  font-size: .95rem; font-weight: 500;
  border: 1px solid transparent; cursor: pointer;
  transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary {
  background: var(--c-primary); color: #fff; border-color: var(--c-primary);
}
.btn-primary:hover:not(:disabled) { background: var(--c-primary-hover); }
.btn-ghost {
  background: transparent; color: var(--c-text-secondary);
  border-color: var(--c-border);
}
.btn-ghost:hover:not(:disabled) { background: var(--c-bg); }

/* ===== Congratulations ===== */
.congrats-hero { text-align: center; margin-bottom: 32px; }
.congrats-fireworks { font-size: 3rem; margin-bottom: 12px; animation: bounce 1s ease infinite alternate; }
@keyframes bounce { from { transform: translateY(0); } to { transform: translateY(-12px); } }
.congrats-hero h2 { font-size: 2rem; margin-bottom: 8px; }
.congrats-hero p { color: var(--c-text-secondary); font-size: 1.1rem; }
.congrats-body h3 { margin: 24px 0 12px; font-size: 1.1rem; }
.congrats-body .command-block { margin: 8px 0; }

/* ===== Sidebar Toggle (mobile) ===== */
.sidebar-toggle {
  display: none;
  position: fixed; bottom: 20px; left: 20px; z-index: 200;
  width: 48px; height: 48px; border-radius: 50%;
  background: var(--c-primary); color: #fff; border: none;
  font-size: 1.3rem; cursor: pointer;
  box-shadow: var(--shadow-lg);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    width: 280px;
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-toggle { display: flex; align-items: center; justify-content: center; }
  .main-content { margin-left: 0; padding: 24px 16px; }
  .welcome-hero h2 { font-size: 1.4rem; }
  .option-cards { flex-direction: column; }
  .account-cards { flex-direction: column; }
  .step-actions { flex-direction: column; }
  .step-actions-right { width: 100%; justify-content: flex-end; }
}