:root {
  --bg: #f4f6fb;
  --card: #ffffff;
  --ink: #0f172a;
  --muted: #64748b;
  --accent: #4f46e5;
  --accent-soft: #eef2ff;
  --line: #e2e8f0;
  --danger: #ef4444;
  --radius: 14px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.06), 0 8px 24px rgba(15, 23, 42, 0.05);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 28px 24px 20px;
  max-width: 860px;
  margin: 0 auto;
  width: 100%;
}

h1 { margin: 0; font-size: 26px; letter-spacing: -0.3px; }
.subtitle { margin: 6px 0 0; color: var(--muted); font-size: 14px; }

main {
  width: 100%;
  max-width: 860px;
  margin: 0 auto;
  padding: 0 24px 24px;
  flex: 1;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.summary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 12px;
  margin-bottom: 16px;
}

.summary-card { padding: 16px 18px; display: flex; flex-direction: column; gap: 4px; }
.label { color: var(--muted); font-size: 13px; }
.value { font-size: 24px; font-weight: 700; letter-spacing: -0.4px; }

.form-card { padding: 16px; margin-bottom: 20px; }
#expense-form {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr auto;
  gap: 10px;
}

input, select {
  font: inherit;
  color: var(--ink);
  background: #f8fafc;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  min-width: 0;
}
input:focus, select:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  background: #fff;
}

.btn {
  font: inherit;
  font-weight: 600;
  border-radius: 10px;
  border: 1px solid transparent;
  padding: 10px 14px;
  cursor: pointer;
}
.btn.primary { background: var(--accent); color: #fff; }
.btn.primary:hover { background: #4338ca; }
.btn.ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn.ghost:hover { background: var(--accent-soft); }
.btn.remove {
  background: transparent;
  color: var(--muted);
  font-size: 20px;
  line-height: 1;
  padding: 4px 10px;
}
.btn.remove:hover { color: var(--danger); background: #fef2f2; }

.list-section { display: flex; flex-direction: column; gap: 12px; }
.list-toolbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.list-toolbar h2 { margin: 0; font-size: 18px; }

.expense-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.expense-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 14px;
}

.expense-details { display: flex; flex-direction: column; gap: 2px; flex: 1; min-width: 0; }
.expense-description { font-weight: 600; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.expense-meta { color: var(--muted); font-size: 13px; }
.expense-amount { font-weight: 700; white-space: nowrap; }

.empty-state { color: var(--muted); text-align: center; padding: 28px 0; }

.app-footer {
  padding: 18px 24px;
  text-align: center;
  color: var(--muted);
  font-size: 13px;
}
.app-footer a { color: var(--accent); text-decoration: none; }
.app-footer a:hover { text-decoration: underline; }

@media (max-width: 640px) {
  .app-header { flex-direction: column; align-items: flex-start; }
  #expense-form { grid-template-columns: 1fr 1fr; }
  #expense-form input#description { grid-column: 1 / -1; }
  #expense-form button { grid-column: 1 / -1; }
}