:root {
  --bg-color: #f4f4f4;
  --card-bg: #ffffff;
  --text-color: #111;
  --border-color: #ddd;
  --accent: #28a745;
}

body.dark {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --text-color: #e5e7eb;
  --border-color: #334155;
  --accent: #22c55e;
}

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

body {
  background-color: var(--bg-color);
  color: var(--text-color);
  font-family: system-ui, sans-serif;
}

/* Theme toggle */
.theme-toggle {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 10px;
}

.theme-toggle i {
  font-size: 20px;
  cursor: pointer;
  color: var(--text-color);
}

/* Container */
.container {
  max-width: 800px;
  margin: 50px auto;
  padding: 20px;
  background-color: var(--card-bg);
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.container h1 {
  text-align: center;
  margin-bottom: 20px;
}

/* Form */
form {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

form button {
  background-color: var(--accent);
  color: #fff;
  border: none;
  cursor: pointer;
  padding: 14px;
  border-radius: 6px;
}

form button:hover {
  opacity: 0.9;
}

/* Input with icons */
.input-group {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background-color: var(--card-bg);
}

.input-group i {
  color: var(--text-color);
  opacity: 0.7;
}

.input-group input,
.input-group select {
  border: none;
  outline: none;
  width: 100%;
  background: transparent;
  color: var(--text-color);
  background-color: var(--card-bg);
  font-size: 14px;
}

/* Table */
.expense-table {
  overflow-x: auto;
}

.expense-table table {
  width: 100%;
  border-collapse: collapse;
  min-width: 600px;
}

.expense-table th,
.expense-table td {
  padding: 10px;
  border: 1px solid var(--border-color);
}

.expense-table th {
  background-color: rgba(0, 0, 0, 0.05);
}

/* Total */
.total-amount {
  text-align: right;
  font-size: 18px;
  margin-top: 10px;
  
}

/* Filter */
.filter {
  margin-bottom: 20px;
  text-align: right;
}

.filter select {
  padding: 8px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  background-color: var(--card-bg);
  color: var(--text-color);
}

/* Mobile */
@media (max-width: 600px) {
  .container {
    margin: 15px;
    padding: 15px;
  }

  form {
    flex-direction: column;
  }

  form button {
    width: 100%;
  }

  .total-amount {
    text-align: center;
    font-size: 16px;
    display: none;
  }

  .filter {
    text-align: left;
  }

  .theme-toggle i {
    font-size: 22px;
  }
}

@media (max-width: 400px) {
  h1 {
    font-size: 22px;
  }

  .total-amount {
    font-size: 14px;
    display: none;
  }
}