:root {
    --primary: #4F46E5;
    --primary-hover: #4338CA;
    --bg-color: #F3F4F6;
    --card-bg: #FFFFFF;
    --text-main: #1F2937;
    --text-muted: #6B7280;
    --border-color: #E5E7EB;
    --error: #EF4444;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    padding: 2rem;
    min-height: 100vh;
}

#app {
    width: 100%;
    max-width: 500px;
}

.view {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    animation: fadeIn 0.3s ease;
}

.hidden {
    display: none !important;
}

.card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

h2 {
    margin-bottom: 1.5rem;
    color: var(--text-main);
    text-align: center;
}

.error-msg {
    color: var(--error);
    font-size: 0.875rem;
    margin-bottom: 1rem;
    text-align: center;
    min-height: 20px;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 0.75rem 1rem;
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    outline: none;
    transition: border-color 0.2s;
}

input[type="text"]:focus,
input[type="password"]:focus {
    border-color: var(--primary);
}

.auth-buttons {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    flex: 1;
}

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

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

.btn.secondary {
    background-color: var(--bg-color);
    color: var(--text-main);
}

.btn.secondary:hover {
    background-color: var(--border-color);
}

.btn.text-btn {
    background: none;
    color: var(--text-muted);
    padding: 0.5rem;
    flex: none;
}

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

.dashboard-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.dashboard-header h2 {
    margin-bottom: 0;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.todo-form {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 2rem;
}

.todo-form input {
    margin-bottom: 0;
}

.todo-form .btn {
    flex: none;
}

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

.todo-item {
    display: flex;
    align-items: center;
    padding: 1rem;
    background: var(--bg-color);
    border-radius: 8px;
    gap: 1rem;
    transition: transform 0.2s;
}

.todo-item:hover {
    transform: translateX(4px);
}

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

.todo-checkbox {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary);
}

.todo-text {
    flex: 1;
    font-size: 1rem;
    word-break: break-word;
}

.delete-btn {
    background: none;
    border: none;
    color: var(--error);
    cursor: pointer;
    padding: 0.5rem;
    opacity: 0.5;
    transition: opacity 0.2s;
}

.todo-item:hover .delete-btn {
    opacity: 1;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}