:root {
  /* Default Dark Mode Colors (1.1) */
  --bg-color: #121212;
  --card-bg: #1e1e1e;
  --text-color: #e0e0e0;
  --text-secondary: #a0a0a0;
  --primary-color: #bb86fc;
  --primary-hover: #3700b3;
  --accent-color: #03dac6;
  --border-color: #333;
  --input-bg: #2c2c2c;
}

/* Light Mode Override Class */
[data-theme="light"] {
  --bg-color: #f4f4f9;
  --card-bg: #ffffff;
  --text-color: #333333;
  --text-secondary: #666666;
  --primary-color: #6200ee;
  --primary-hover: #3700b3;
  --accent-color: #018786;
  --border-color: #ddd;
  --input-bg: #ffffff;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  margin: 0;
  padding: 0;
  transition: background-color 0.3s, color 0.3s;
}

header {
  background-color: var(--card-bg);
  padding: 1rem 2rem;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

h1,
h2,
h3 {
  margin: 0;
}

button {
  background-color: var(--primary-color);
  color: #fff;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 1rem;
  transition: background-color 0.2s;
}

button:hover {
  background-color: var(--primary-hover);
}

/* Toggle Switch */
.theme-toggle {
  background: none;
  border: 1px solid var(--text-color);
  color: var(--text-color);
  margin-right: 1rem;
}

.container {
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

/* Cards & Grid */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.5rem;
  margin-top: 1rem;
}

.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem;
  text-align: center;
  cursor: pointer;
  transition: transform 0.2s;
}

.card:hover {
  transform: translateY(-5px);
}

.card h3 {
  color: var(--accent-color);
}

/* Forms & Inputs */
input,
select {
  background-color: var(--input-bg);
  color: var(--text-color);
  border: 1px solid var(--border-color);
  padding: 0.5rem;
  border-radius: 4px;
  width: 100%;
  margin-bottom: 1rem;
  box-sizing: border-box;
}

/* Modals */
.modal {
  display: none;
  position: fixed;
  z-index: 100;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.6);
}

.modal-content {
  background-color: var(--card-bg);
  margin: 10% auto;
  padding: 2rem;
  border: 1px solid var(--border-color);
  width: 90%;
  max-width: 400px;
  border-radius: 8px;
  position: relative;
}

.close {
  color: var(--text-secondary);
  float: right;
  font-size: 28px;
  font-weight: bold;
  cursor: pointer;
}

.close:hover {
  color: var(--text-color);
}

/* Stats Section */
#stats-display {
  background-color: var(--card-bg);
  padding: 1.5rem;
  border-radius: 8px;
  margin-top: 1rem;
}

/* 9.2 Chart Container */
.chart-container {
  position: relative;
  height: 300px;
  width: 100%;
  margin-top: 2rem;
}

/* 7.4 Loading Overlay */
#loading-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  z-index: 999;
  justify-content: center;
  align-items: center;
  color: white;
  font-size: 1.5rem;
  flex-direction: column;
}

.spinner {
  border: 4px solid rgba(255, 255, 255, 0.3);
  border-top: 4px solid var(--primary-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
  margin-bottom: 1rem;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

/* Utility */
.hidden {
  display: none;
}

.password-note {
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  text-align: left;
}