/* ============================= */
/*         ROOT VARIABLES        */
/* ============================= */
:root {
  /* Dark Theme Colors */
  --bg-dark: #0a0f1c; /* Background color dark mode */
  --card-dark: #141a2a; /* Card background dark */
  --muted-dark: #a4acc4; /* Muted text color dark */
  --accent1-dark: #00e6ff; /* Accent color 1 dark */
  --accent2-dark: #ff5f9e; /* Accent color 2 dark */
  --glass-dark: rgba(255, 255, 255, 0.05); /* Glass effect dark mode */

  /* Light Theme Colors */
  --bg-light: #eef3fb; /* Background light mode */
  --card-light: #ffffff; /* Card background light */
  --muted-light: #444; /* Muted text color light */
  --accent1-light: #0066ff; /* Accent color 1 light */
  --accent2-light: #ff477e; /* Accent color 2 light */
  --glass-light: rgba(255, 255, 255, 0.6); /* Glass effect light mode */

  /* Common colors */
  --success: #34d399; /* Success green */
  --danger: #ff6b6b; /* Error red */

  /* UI defaults */
  --radius: 12px; /* Border radius for rounded corners */
  --transition: all 0.25s ease; /* Smooth transition for animations */
}

/* ============================= */
/*     GLOBAL ELEMENT RESET      */
/* ============================= */
* {
  box-sizing: border-box; /* Include padding & border in element's total width/height */
}

html, body {
  height: 100%;
  margin: 0;
  font-family: 'Inter', ui-sans-serif, system-ui, Segoe UI, Roboto, Arial;
  transition: var(--transition); /* Smooth theme change */
}

/* ============================= */
/*      DARK THEME DEFAULTS      */
/* ============================= */
body {
  background: radial-gradient(circle at top, var(--bg-dark), #050812); /* Dark gradient background */
  color: #e8f1ff; /* Light text for dark background */
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 28px;
}

/* ============================= */
/*       APP CONTAINER BOX       */
/* ============================= */
.app {
  width: 100%;
  max-width: 980px;
  background: var(--glass-dark);
  border-radius: 18px;
  padding: 20px 22px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(10px); /* Frosted glass effect */
  transition: var(--transition);
}

/* ============================= */
/*           HEADER BAR          */
/* ============================= */
.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.app-header h1 {
  margin: 0;
  font-size: 1.7rem;
  letter-spacing: 0.5px;
  background: linear-gradient(90deg, var(--accent1-dark), var(--accent2-dark));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

/* ============================= */
/*       HEADER CONTROLS         */
/* ============================= */
.controls {
  display: flex;
  gap: 10px;
  align-items: center;
}

.controls input[type=search],
.controls select {
  padding: 8px 10px;
  border-radius: var(--radius);
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: var(--glass-dark);
  color: inherit;
  min-width: 160px;
  transition: var(--transition);
}

/* Hover effect for controls */
.controls input[type=search]:hover,
.controls select:hover {
  transform: scale(1.03);
  border-color: var(--accent1-dark);
  box-shadow: 0 0 8px var(--accent1-dark);
}

/* ============================= */
/*        THEME TOGGLE BTN       */
/* ============================= */
.icon-btn {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.08);
  padding: 8px;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 1.2rem;
  transition: var(--transition);
}

.icon-btn:hover {
  background: linear-gradient(90deg, var(--accent1-dark), var(--accent2-dark));
  color: #fff;
  transform: rotate(10deg) scale(1.1);
  box-shadow: 0 4px 15px var(--accent1-dark);
}

/* ============================= */
/*         ADD PANEL ROW         */
/* ============================= */
.add-panel {
  margin-top: 18px;
}

.field-row {
  display: flex;
  gap: 10px;
  align-items: center;
}

.field-row input[type=text],
.field-row select,
.field-row input[type=date] {
  padding: 10px 12px;
  border-radius: var(--radius);
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: transparent;
  color: inherit;
  flex: 1;
  transition: var(--transition);
}

/* Hover effect for inputs */
.field-row input:hover,
.field-row select:hover,
.field-row input[type=date]:hover {
  border-color: var(--accent2-dark);
  box-shadow: 0 0 8px var(--accent2-dark);
}

/* Add button styling */
#addBtn {
  padding: 10px 14px;
  border-radius: var(--radius);
  border: none;
  background: linear-gradient(90deg, var(--accent1-dark), var(--accent2-dark));
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

#addBtn:hover {
  transform: translateY(-2px) scale(1.05);
  box-shadow: 0 4px 15px var(--accent2-dark);
}

/* Error text */
.input-error {
  color: var(--danger);
  font-size: 0.9rem;
  margin-top: 8px;
  min-height: 1.1em;
}

/* ============================= */
/*          TASK LIST UI         */
/* ============================= */
.task-list {
  list-style: none;
  padding: 0;
  margin: 16px 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* Individual task card */
.task-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  border-radius: var(--radius);
  background: var(--glass-dark);
  border: 1px solid rgba(255, 255, 255, 0.05);
  transition: var(--transition);
}

.task-card:hover {
  transform: scale(1.02);
  box-shadow: 0 4px 20px rgba(0, 255, 255, 0.15);
}

/* Task checkbox */
.checkbox {
  width: 20px;
  height: 20px;
  border-radius: 6px;
  border: 2px solid rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.checkbox.checked {
  background: linear-gradient(90deg, var(--accent1-dark), var(--accent2-dark));
  border: none;
  color: #fff;
}

/* Task text & meta */
.task-main {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.task-title {
  font-weight: 600;
}

.task-meta {
  font-size: 0.85rem;
  color: var(--muted-dark);
  margin-top: 4px;
}

/* Priority label colors */
.priority-high {
  background: rgba(255, 90, 90, 0.15);
  color: #ff7b7b;
}
.priority-medium {
  background: rgba(255, 206, 80, 0.12);
  color: #ffd580;
}
.priority-low {
  background: rgba(113, 243, 211, 0.1);
  color: #7ee7c7;
}

/* Completed task style */
.task-title.completed {
  text-decoration: line-through;
  color: rgba(255, 255, 255, 0.45);
}

/* Empty task note */
.empty-note {
  color: var(--muted-dark);
  text-align: center;
  margin-top: 10px;
}

/* ============================= */
/*           LIGHT THEME         */
/* ============================= */
body.light {
  background: linear-gradient(135deg, #f7faff, #dde7f6);
  color: #0b1220;
}

body.light .app {
  background: var(--glass-light);
  box-shadow: 0 8px 30px rgba(12, 20, 40, 0.08);
  backdrop-filter: blur(8px);
}

body.light .app-header h1 {
  background: linear-gradient(90deg, var(--accent1-light), var(--accent2-light));
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

body.light .controls input[type=search],
body.light .controls select {
  background: rgba(255, 255, 255, 0.85);
  border-color: rgba(0, 0, 0, 0.06);
  color: #0b1220;
}

body.light .icon-btn {
  border: 1px solid rgba(0, 0, 0, 0.06);
}

body.light .icon-btn:hover {
  background: linear-gradient(90deg, var(--accent1-light), var(--accent2-light));
  color: #fff;
}

body.light #addBtn {
  background: linear-gradient(90deg, var(--accent1-light), var(--accent2-light));
}

body.light .task-card {
  background: var(--card-light);
  border-color: rgba(0, 0, 0, 0.05);
}

body.light .task-meta {
  color: var(--muted-light);
}

body.light .empty-note {
  color: var(--muted-light);
}

body.light .bulk-actions button {
  background: linear-gradient(90deg, var(--accent1-light), var(--accent2-light));
}

/* ============================= */
/*     BULK ACTION BUTTONS       */
/* ============================= */
.bulk-actions button {
  background: linear-gradient(90deg, var(--accent1-dark), var(--accent2-dark));
  border: none;
  color: white;
  padding: 8px 12px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  cursor: pointer;
  transition: var(--transition);
}

.bulk-actions button:hover {
  transform: scale(1.05);
  box-shadow: 0 4px 12px var(--accent1-dark);
}

/* ============================= */
/*         RESPONSIVENESS        */
/* ============================= */
@media (max-width: 700px) {
  .field-row {
    flex-direction: column;
    align-items: stretch;
  }
  .controls {
    flex-wrap: wrap;
  }
}