/* 
  ✨ DESIGN SYSTEM: To-Do List App (Vitruvian Strategist Edition)
  Focus: Modern Aesthetics, Accessibility, and Micro-interactions.
*/

:root {
  /* 🎨 Primary Palette */
  --clr-primary: #6366f1; /* Indigo */
  --clr-accent: #10b981;  /* Success Emerald */
  --clr-danger: #ef4444;  /* Red Alert */
  --clr-warning: #f59e0b; /* Caution Amber */

  /* 🌓 Neutrals & Dark Mode Ready */
  --clr-bg: #f8fafc;
  --clr-surface: #ffffff;
  --clr-text-main: #1e293b;
  --clr-text-sub: #64748b;
  --clr-border: #e2e8f0;

  /* 📏 Layout & Spacing */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 24px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);

  /* 🕒 Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* 🧱 Global Resets */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--clr-bg);
  color: var(--clr-text-main);
  line-height: 1.6;
  min-height: 100vh;
  padding: 2rem 1rem;
  display: flex;
  justify-content: center;
}

/* 🖼️ Layout Utilities */
.container {
  width: 100%;
  max-width: 600px;
  background: var(--clr-surface);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-lg);
}

/* ⌨️ Accessibility: Focus Styles */
:focus-visible {
  outline: 3px solid var(--clr-primary);
  outline-offset: 2px;
}

/* 🏷️ Components */
.heading {
  font-size: 2.25rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--clr-primary), #a855f7);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: 0.5rem;
}

.subheading {
  color: var(--clr-text-sub);
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 2rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.input-group {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 2.5rem;
}

input[type="text"] {
  flex-grow: 1;
  padding: 1rem 1.25rem;
  border: 2px solid var(--clr-border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  transition: var(--transition-fast);
}

.priority-select {
  padding: 0 1rem;
  border: 2px solid var(--clr-border);
  border-radius: var(--radius-md);
  background-color: white;
  color: var(--clr-text-main);
  font-weight: 500;
  cursor: pointer;
}

.priority-select:focus {
  border-color: var(--clr-primary);
  outline: none;
}

input[type="text"]:focus {
  border-color: var(--clr-primary);
  box-shadow: 0 0 0 1px var(--clr-primary);
}

.btn {
  cursor: pointer;
  padding: 1rem 1.5rem;
  border: none;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: 1rem;
  transition: var(--transition-normal);
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-primary {
  background: var(--clr-primary);
  color: white;
}

.btn-primary:hover {
  background: #4f46e5;
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-sm {
  padding: 0.5rem 0.75rem;
  font-size: 0.75rem;
  letter-spacing: 0.025em;
  text-transform: uppercase;
  border-radius: var(--radius-sm);
}

/* 📃 Task List Styles */
.task-item {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem;
  background: var(--clr-bg);
  border-radius: var(--radius-md);
  margin-bottom: 1rem;
  transition: var(--transition-normal);
  border: 1px solid transparent;
}

.task-item:hover {
  transform: scale(1.01);
  box-shadow: var(--shadow-md);
}

.checkbox {
  width: 24px;
  height: 24px;
  cursor: pointer;
  accent-color: var(--clr-accent);
}

.task-text {
  flex-grow: 1;
  font-weight: 500;
}

/* 🏷️ Priority Badges */
.priority-badge {
  font-size: 0.65rem;
  font-weight: 800;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-right: 0.5rem;
}

.priority-urgent { background: #fee2e2; color: #991b1b; }
.priority-high { background: #ffedd5; color: #9a3412; }
.priority-medium { background: #dcfce7; color: #166534; }
.priority-low { background: #f1f5f9; color: #475569; }

.task-item.completed .task-text {
  text-decoration: line-through;
  color: var(--clr-text-sub);
}

.task-item.completed {
  opacity: 0.7;
}

/* 📊 Micro-animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.btn-danger-icon {
  background: transparent;
  color: var(--clr-text-sub);
  padding: 0.5rem;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-danger-icon:hover {
  background: #fee2e2;
  color: var(--clr-danger);
  transform: scale(1.1);
}

.btn-danger-icon svg {
  transition: transform 0.2s ease;
}

.animate-in {
  animation: fadeIn var(--transition-normal);
}

/* ⏲️ Pomodoro Timer Styles */
.timer-card {
  background: linear-gradient(135deg, #f1f5f9 0%, #ffffff 100%);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: 2rem;
  margin-bottom: 2.5rem;
  text-align: center;
  transition: var(--transition-normal);
}

.timer-modes {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  background: var(--clr-bg);
  padding: 0.4rem;
  border-radius: var(--radius-md);
  width: fit-content;
  margin-inline: auto;
}

.mode-btn {
  border: none;
  background: transparent;
  padding: 0.5rem 1rem;
  font-weight: 600;
  font-size: 0.875rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--clr-text-sub);
  transition: var(--transition-fast);
}

.mode-btn:hover {
  color: var(--clr-text-main);
}

.mode-btn.active {
  background: white;
  color: var(--clr-primary);
  box-shadow: var(--shadow-sm);
}

.session-label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--clr-text-sub);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
}

.timer-card:hover {
  border-color: var(--clr-primary);
  box-shadow: var(--shadow-md);
}

.timer-display {
  font-size: 4rem;
  font-weight: 800;
  color: var(--clr-primary);
  font-variant-numeric: tabular-nums;
  margin-bottom: 1rem;
  letter-spacing: -0.05em;
  display: flex;
  justify-content: center;
  align-items: center;
}

#timer-minutes, #timer-seconds {
  min-width: 1.5ch;
  padding: 0 0.2rem;
  border-radius: var(--radius-sm);
  transition: var(--transition-fast);
  cursor: text;
}

#timer-minutes:hover, #timer-seconds:hover {
  background: #f1f5f9;
}

#timer-minutes:focus, #timer-seconds:focus {
  background: #e2e8f0;
  outline: none;
  box-shadow: 0 0 0 2px var(--clr-primary);
}

.timer-controls {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.btn-primary-outline {
  background: transparent;
  border: 2px solid var(--clr-primary);
  color: var(--clr-primary);
}

.btn-primary-outline:hover {
  background: var(--clr-primary);
  color: white;
}

.btn-ghost {
  background: transparent;
  color: var(--clr-text-sub);
}

.btn-ghost:hover {
  background: var(--clr-bg);
  color: var(--clr-text-main);
}