/* ============================================
   Todo List - Design with Brand Colors
   ============================================ */

:root {
  --color-navy: #0B1426;
  --color-blue: #003DB5;
  --color-accent: #0055FF;
  --color-navy-light: #0f1e35;
  --color-navy-lighter: #15273d;
  --color-navy-soft: #1a3152;
  --color-blue-muted: rgba(0, 61, 181, 0.25);
  --color-accent-muted: rgba(0, 85, 255, 0.2);
  --color-accent-glow: rgba(0, 85, 255, 0.4);
  --color-text: #e8eef8;
  --color-text-muted: #8fa3c4;
  --color-white: #ffffff;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.4);
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  min-height: 100vh;
  font-family: 'Poppins', -apple-system, BlinkMacSystemFont, sans-serif;
  background: linear-gradient(165deg, var(--color-navy) 0%, var(--color-navy-light) 40%, var(--color-navy-lighter) 100%);
  color: var(--color-text);
  padding: 2rem 1rem 4rem;
  position: relative;
  overflow-x: hidden;
}

/* Subtle background pattern */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-image: 
    radial-gradient(ellipse 80% 50% at 50% -20%, var(--color-accent-muted) 0%, transparent 50%),
    radial-gradient(ellipse 60% 40% at 100% 80%, var(--color-blue-muted) 0%, transparent 40%);
  pointer-events: none;
  z-index: 0;
}

/* ============================================
   Layout & Container
   ============================================ */

.app-container {
  max-width: 560px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

/* ============================================
   Header
   ============================================ */

header {
  text-align: center;
  margin-bottom: 2.5rem;
}

header h2 {
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============================================
   Form - Add Todo & Filter
   ============================================ */

.form-wrapper {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 2rem;
}

.add-todo-row {
  display: flex;
  gap: 0.5rem;
  align-items: stretch;
}

.todo-input {
  flex: 1;
  min-width: 0;
  padding: 0.875rem 1.25rem;
  font-size: 1rem;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-navy-lighter);
  border: 2px solid var(--color-navy-soft);
  border-radius: var(--radius-md);
  transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
}

.todo-input::placeholder {
  color: var(--color-text-muted);
}

.todo-input:hover {
  border-color: var(--color-blue);
  background: var(--color-navy-soft);
}

.todo-input:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 4px var(--color-accent-muted);
}

.todo-button {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, var(--color-blue) 0%, var(--color-accent) 100%);
  border: none;
  border-radius: var(--radius-md);
  color: var(--color-white);
  font-size: 1.25rem;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), opacity var(--transition);
  box-shadow: var(--shadow-sm);
}

.todo-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--color-accent-glow);
}

.todo-button:active {
  transform: translateY(0);
}

/* Filter Select */
.filter-row {
  display: flex;
  justify-content: stretch;
}

.filter-todo {
  width: 100%;
  padding: 0.75rem 1rem;
  padding-right: 2.5rem;
  font-size: 0.95rem;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-navy-lighter);
  border: 2px solid var(--color-navy-soft);
  border-radius: var(--radius-md);
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12' fill='%238fa3c4'%3E%3Cpath d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  transition: border-color var(--transition), background var(--transition);
}

.filter-todo:hover {
  border-color: var(--color-blue);
  background-color: var(--color-navy-soft);
}

.filter-todo:focus {
  outline: none;
  border-color: var(--color-accent);
}

.filter-todo option {
  background: var(--color-navy-light);
  color: var(--color-text);
}

/* ============================================
   Todo List Container
   ============================================ */

.todo-container {
  background: rgba(15, 30, 53, 0.6);
  backdrop-filter: blur(12px);
  border: 1px solid rgba(0, 85, 255, 0.12);
  border-radius: var(--radius-lg);
  padding: 0.5rem;
  box-shadow: var(--shadow-md);
}

.todo-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

/* ============================================
   Todo Items
   ============================================ */

.todo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1rem;
  background: var(--color-navy-lighter);
  border: 1px solid var(--color-navy-soft);
  border-radius: var(--radius-md);
  transition: all var(--transition);
}

.todo:hover {
  border-color: rgba(0, 85, 255, 0.3);
  background: var(--color-navy-soft);
}

.todo.completed {
  opacity: 0.7;
}

.todo.completed .todo-item {
  text-decoration: line-through;
  color: var(--color-text-muted);
}

.todo-item {
  flex: 1;
  min-width: 0;
  font-size: 1rem;
  line-height: 1.5;
  word-break: break-word;
}

/* Buttons */
.complete-btn,
.trash-btn {
  flex-shrink: 0;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition);
  background: transparent;
  color: var(--color-text-muted);
}

.complete-btn:hover {
  color: #22c55e;
  background: rgba(34, 197, 94, 0.15);
}

.todo.completed .complete-btn {
  color: #22c55e;
  background: rgba(34, 197, 94, 0.15);
}

.todo.completed .complete-btn:hover {
  color: #16a34a;
  background: rgba(34, 197, 94, 0.25);
}

.trash-btn:hover {
  color: #ef4444;
  background: rgba(239, 68, 68, 0.15);
}

.complete-btn i,
.trash-btn i {
  font-size: 0.9rem;
}

/* Empty state */
.todo-list:empty::before {
  content: 'No tasks yet';
  display: block;
  text-align: center;
  padding: 2rem 1rem;
  color: var(--color-text-muted);
  font-size: 0.95rem;
}