/* BillShare UI — clean finance app: clear hierarchy, soft surfaces, mobile-first */
:root {
  --bg: #f4f6fa;
  --bg-elevated: #ffffff;
  --panel: #ffffff;
  --panel-soft: #f8fafc;
  --border: #e2e8f0;
  --border-strong: #cbd5e1;
  --text: #0f172a;
  --muted: #64748b;
  --faint: #94a3b8;
  --primary: #2563eb;
  --primary-soft: #eff6ff;
  --primary-hover: #1d4ed8;
  --accent: #059669;
  --accent-soft: #ecfdf5;
  --warn: #d97706;
  --warn-soft: #fffbeb;
  --danger: #dc2626;
  --danger-soft: #fef2f2;
  --purple: #7c3aed;
  --purple-soft: #f5f3ff;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 8px 24px rgba(15, 23, 42, 0.06);
  --shadow-lg: 0 4px 6px rgba(15, 23, 42, 0.04), 0 20px 40px rgba(15, 23, 42, 0.08);
  --radius: 16px;
  --radius-sm: 12px;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  --safe-bottom: env(safe-area-inset-bottom, 0px);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1220;
    --bg-elevated: #111a2e;
    --panel: #152038;
    --panel-soft: #1a2740;
    --border: rgba(148, 163, 184, 0.16);
    --border-strong: rgba(148, 163, 184, 0.28);
    --text: #e8eef9;
    --muted: #93a4c3;
    --faint: #6b7c9b;
    --primary: #60a5fa;
    --primary-soft: rgba(96, 165, 250, 0.12);
    --primary-hover: #93c5fd;
    --accent: #34d399;
    --accent-soft: rgba(52, 211, 153, 0.12);
    --warn: #fbbf24;
    --warn-soft: rgba(251, 191, 36, 0.12);
    --danger: #f87171;
    --danger-soft: rgba(248, 113, 113, 0.12);
    --purple: #a78bfa;
    --purple-soft: rgba(167, 139, 250, 0.12);
    --shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
    --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.45);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-tap-highlight-color: transparent; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
  font-size: 15px;
  -webkit-text-size-adjust: 100%;
  overscroll-behavior-y: none;
}
button, input, select, textarea { font: inherit; color: inherit; }

/* Mobile: inputs at 16px prevent iOS auto-zoom; ≥44px touch targets */
@media (max-width: 640px) {
  input, select, textarea { font-size: 16px; }
  .btn { min-height: 44px; }
  .nav button { min-height: 40px; }
}

/* Top bar */
.topbar {
  position: sticky; top: 0; z-index: 40;
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px;
  padding: 12px 16px;
  background: color-mix(in srgb, var(--bg-elevated) 92%, transparent);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(14px);
}
.brand {
  font-weight: 800; letter-spacing: -0.03em;
  display: flex; align-items: center; gap: 10px; font-size: 17px;
}
.logo {
  width: 36px; height: 36px; border-radius: 12px;
  background: linear-gradient(135deg, #2563eb, #06b6d4);
  display: grid; place-items: center; color: #fff; font-size: 16px;
  box-shadow: 0 6px 16px rgba(37, 99, 235, 0.35);
}
.nav {
  display: flex; flex-wrap: wrap; gap: 4px; flex: 1; justify-content: center;
}
.nav button {
  background: transparent; border: none; color: var(--muted);
  padding: 8px 14px; border-radius: 999px; cursor: pointer; font-size: 13px; font-weight: 600;
  transition: 0.15s ease;
}
.nav button:hover { color: var(--text); background: var(--panel-soft); }
.nav button.active {
  color: var(--primary); background: var(--primary-soft);
}
.top-right { display: flex; align-items: center; gap: 8px; font-size: 13px; }
.lang {
  display: flex; border: 1px solid var(--border); border-radius: 999px; overflow: hidden;
  background: var(--panel);
}
.lang button {
  border: none; background: transparent; color: var(--muted);
  padding: 6px 11px; cursor: pointer; font-size: 12px; font-weight: 700;
}
.lang button.active { background: var(--primary-soft); color: var(--primary); }
#userLabel {
  max-width: 120px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  color: var(--muted); font-weight: 600;
}

main { max-width: 880px; margin: 0 auto; padding: 20px 16px calc(88px + var(--safe-bottom)); }

/* Cards */
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  margin-bottom: 14px;
  box-shadow: var(--shadow);
}
.card.soft { background: var(--panel-soft); box-shadow: none; }
.card.hero {
  background: linear-gradient(145deg, var(--primary-soft), var(--panel));
  border-color: color-mix(in srgb, var(--primary) 25%, var(--border));
}
h1 { font-size: clamp(22px, 4vw, 28px); margin-bottom: 6px; letter-spacing: -0.03em; font-weight: 800; }
h2 { font-size: 17px; margin-bottom: 10px; font-weight: 700; letter-spacing: -0.02em; }
h3 { font-size: 14px; margin-bottom: 8px; font-weight: 700; color: var(--muted); }
.sub { color: var(--muted); font-size: 14px; margin-bottom: 14px; }
.muted { color: var(--muted); }
.faint { color: var(--faint); }

.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 720px) {
  .grid2 { grid-template-columns: 1fr; }
  .nav { order: 3; flex: 0 0 100%; justify-content: flex-start; flex-wrap: wrap; padding-bottom: 2px; }
  .nav button { flex-shrink: 0; padding: 8px 11px; font-size: 12.5px; }
}

/* Forms */
.field { margin-bottom: 12px; }
.field label {
  display: block; font-size: 12px; font-weight: 600; color: var(--muted);
  margin-bottom: 6px; letter-spacing: 0.01em;
}
.field input, .field select, .field textarea {
  width: 100%; background: var(--panel-soft);
  border: 1px solid var(--border); color: var(--text);
  border-radius: var(--radius-sm); padding: 11px 13px; outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.field input:focus, .field select:focus, .field textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 20%, transparent);
  background: var(--panel);
}
.field textarea { min-height: 88px; resize: vertical; }
.row { display: flex; gap: 10px; flex-wrap: wrap; }
.row > * { flex: 1; min-width: 120px; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  border: none; border-radius: 12px; padding: 11px 16px;
  font-size: 13px; font-weight: 700; cursor: pointer;
  transition: transform 0.1s, filter 0.15s, background 0.15s;
  white-space: nowrap;
}
.btn:active { transform: scale(0.98); }
.btn.primary { background: var(--primary); color: #fff; }
.btn.primary:hover { background: var(--primary-hover); }
.btn.ghost {
  background: var(--panel); color: var(--text);
  border: 1px solid var(--border);
}
.btn.ghost:hover { background: var(--panel-soft); }
.btn.success { background: var(--accent-soft); color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 30%, transparent); }
.btn.danger { background: var(--danger-soft); color: var(--danger); border: 1px solid color-mix(in srgb, var(--danger) 30%, transparent); }
.btn.sm { padding: 7px 11px; font-size: 12px; border-radius: 10px; }
.btn.block { width: 100%; }
.btn.kofi {
  background: linear-gradient(135deg, #ff5e5b, #ff7a59); color: #fff;
  box-shadow: 0 8px 20px rgba(255, 94, 91, 0.3);
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* List items */
.list { display: grid; gap: 8px; }
.item {
  display: flex; align-items: center; gap: 12px; padding: 14px;
  border-radius: var(--radius-sm); background: var(--panel-soft);
  border: 1px solid var(--border); transition: border-color 0.15s;
}
.item:hover { border-color: var(--border-strong); }
.item .meta { flex: 1; min-width: 0; }
.item .title { font-weight: 700; font-size: 14px; letter-spacing: -0.01em; }
.item .desc { color: var(--muted); font-size: 12px; margin-top: 2px; }
.item .actions { display: flex; gap: 6px; flex-shrink: 0; flex-wrap: wrap; justify-content: flex-end; }
.amount { font-weight: 800; white-space: nowrap; font-variant-numeric: tabular-nums; letter-spacing: -0.02em; }
.avatar {
  width: 40px; height: 40px; border-radius: 12px; flex-shrink: 0;
  display: grid; place-items: center; font-weight: 800; font-size: 14px; color: #fff;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
}
.avatar.sm { width: 32px; height: 32px; font-size: 12px; border-radius: 10px; }

.badge {
  display: inline-flex; align-items: center;
  font-size: 11px; font-weight: 700; padding: 3px 9px; border-radius: 999px;
  border: 1px solid transparent;
}
.badge.blue { background: var(--primary-soft); color: var(--primary); }
.badge.green { background: var(--accent-soft); color: var(--accent); }
.badge.amber { background: var(--warn-soft); color: var(--warn); }
.badge.purple { background: var(--purple-soft); color: var(--purple); }
.badge.red { background: var(--danger-soft); color: var(--danger); }

.check {
  display: flex; align-items: center; gap: 10px; padding: 10px 12px;
  border-radius: 12px; background: var(--panel-soft); border: 1px solid var(--border);
  margin-bottom: 6px; font-size: 13px; cursor: pointer; font-weight: 600;
}
.check:has(input:checked) { border-color: color-mix(in srgb, var(--primary) 40%, var(--border)); background: var(--primary-soft); }
.check input { width: 16px; height: 16px; accent-color: var(--primary); }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 14px; }
@media (max-width: 600px) { .stats { grid-template-columns: 1fr; } }
.stat {
  padding: 16px; border-radius: var(--radius); background: var(--panel);
  border: 1px solid var(--border); box-shadow: var(--shadow);
}
.stat .label { font-size: 12px; color: var(--muted); font-weight: 600; }
.stat .value { font-size: 22px; font-weight: 800; margin-top: 4px; letter-spacing: -0.03em; font-variant-numeric: tabular-nums; }

/* Type pick */
.type-pick { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 12px; }
@media (max-width: 520px) { .type-pick { grid-template-columns: 1fr; } }
.type-pick button {
  text-align: left; padding: 16px; border-radius: var(--radius-sm); cursor: pointer;
  background: var(--panel-soft); border: 2px solid var(--border); color: var(--text);
  transition: 0.15s ease;
}
.type-pick button.selected {
  border-color: var(--primary); background: var(--primary-soft);
}
.type-pick strong { display: block; margin-bottom: 4px; font-size: 15px; }
.type-pick span { font-size: 12px; color: var(--muted); font-weight: 500; }

/* Invite box */
.invite-box {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  padding: 14px; border-radius: var(--radius-sm);
  background: var(--primary-soft); border: 1px dashed color-mix(in srgb, var(--primary) 40%, transparent);
}
.invite-box code {
  font-family: ui-monospace, Consolas, monospace; font-weight: 800;
  font-size: 15px; letter-spacing: 0.06em; flex: 1; min-width: 140px;
  word-break: break-all;
}

/* Empty state */
.empty {
  text-align: center; padding: 28px 16px; color: var(--muted);
  border: 1px dashed var(--border); border-radius: var(--radius-sm);
  background: var(--panel-soft);
}
.empty .icon { font-size: 32px; margin-bottom: 8px; }

/* Auth */
.auth-wrap { max-width: 420px; margin: 20px auto 0; }
.auth-wrap .card { box-shadow: var(--shadow-lg); }
.auth-hero { text-align: center; margin-bottom: 18px; }
.auth-hero h1 { margin-bottom: 4px; }
.auth-hero .sub { margin: 0 auto; max-width: 330px; }
.logo.lg {
  width: 58px; height: 58px; border-radius: 18px; font-size: 26px;
  margin: 0 auto 14px; box-shadow: 0 10px 26px rgba(37, 99, 235, 0.4);
}
.pass-wrap { position: relative; }
.pass-wrap input { padding-right: 46px; }
.pass-toggle {
  position: absolute; right: 6px; top: 50%; transform: translateY(-50%);
  border: none; background: transparent; cursor: pointer;
  font-size: 15px; padding: 8px; border-radius: 10px; color: var(--muted);
  line-height: 1;
}
.pass-toggle:hover { background: var(--panel-soft); }
.auth-toggle { text-align: center; margin-top: 16px; font-size: 13px; }
.auth-toggle a { color: var(--primary); font-weight: 700; text-decoration: none; }
.auth-toggle a:active { opacity: 0.8; }

/* FAB donate */
.fab-donate {
  position: fixed; left: 16px; bottom: calc(16px + var(--safe-bottom)); z-index: 30;
  text-decoration: none; color: #fff; font-weight: 800; font-size: 13px;
  padding: 12px 16px; border-radius: 999px;
  background: linear-gradient(135deg, #ff5e5b, #ff7a59);
  box-shadow: 0 10px 28px rgba(255, 94, 91, 0.35);
}

/* Toast */
.toast {
  position: fixed; bottom: calc(20px + var(--safe-bottom)); right: 16px; left: 16px;
  max-width: 360px; margin-left: auto;
  background: var(--text); color: var(--bg); padding: 12px 16px; border-radius: 14px;
  display: none; z-index: 60; font-size: 13px; font-weight: 600;
  box-shadow: var(--shadow-lg);
}
.toast.show { display: block; animation: slideUp 0.25s ease; }
@keyframes slideUp {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

/* Modal sheet for edit */
.modal-backdrop {
  position: fixed; inset: 0; z-index: 50;
  background: rgba(15, 23, 42, 0.45); backdrop-filter: blur(4px);
  display: flex; align-items: flex-end; justify-content: center;
  padding: 16px;
}
@media (min-width: 640px) {
  .modal-backdrop { align-items: center; }
}
.modal {
  width: min(520px, 100%); max-height: 90vh; overflow: auto;
  background: var(--panel); border-radius: 20px; padding: 20px;
  border: 1px solid var(--border); box-shadow: var(--shadow-lg);
}

.section-head {
  display: flex; align-items: center; justify-content: space-between;
  gap: 10px; margin-bottom: 12px; flex-wrap: wrap;
}
.pill-tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.note {
  font-size: 12px; color: var(--muted); background: var(--panel-soft);
  border: 1px solid var(--border); border-radius: 12px; padding: 10px 12px; margin-top: 10px;
}

/* Auth divider + OAuth buttons */
.divider {
  display: flex; align-items: center; gap: 10px; margin: 16px 0 12px;
  color: var(--faint); font-size: 12px; font-weight: 600; letter-spacing: 0.03em;
}
.divider::before, .divider::after { content: ""; flex: 1; height: 1px; background: var(--border); }
.oauth-btns { display: grid; gap: 8px; }
.oauth-btns .btn {
  width: 100%; min-height: 48px; font-size: 14px;
  background: var(--panel); color: var(--text);
  border: 1px solid var(--border-strong); box-shadow: var(--shadow);
}
.oauth-btns .btn:hover { background: var(--panel-soft); }
.oauth-btns .btn svg { flex-shrink: 0; }
.oauth-btns .btn span { flex: 1; text-align: center; margin-right: 24px; }

/* Settlement breakdown */
.brk-rows { margin-top: 8px; display: grid; gap: 3px; }
.brk-row { display: flex; align-items: center; gap: 10px; font-size: 12.5px; }
.brk-row .name { flex: 1; min-width: 0; font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.brk-row .muted { font-size: 11.5px; }
.brk-item { align-items: flex-start; }
.formula {
  margin-top: 8px; padding: 10px 12px; background: var(--panel);
  border: 1px solid var(--border); border-radius: 10px;
  font-size: 11.5px; line-height: 1.55; font-family: ui-monospace, Consolas, monospace;
  white-space: pre-wrap; word-break: break-word; color: var(--muted);
}
.hidden { display: none !important; }
.page-actions { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 14px; }
.cat-icon {
  width: 40px; height: 40px; border-radius: 12px; display: grid; place-items: center;
  font-size: 18px; flex-shrink: 0; background: var(--primary-soft);
}