:root {
    --bg-color: #FDFBF7;
    --app-bg: #FFFFFF;
    --border-color: #E6E2D8;
    --text-primary: #2D2825;
    --text-secondary: #7E766D;
    --accent-color: #C16E5A; /* Warm Terracotta */
    --accent-hover: #A85845;
    --danger-color: #E05252;
    --danger-bg: #FDF0F0;
    --shadow-sm: 0 4px 12px rgba(45, 40, 37, 0.04);
    --shadow-md: 0 8px 24px rgba(45, 40, 37, 0.06);
    --shadow-lg: 0 24px 48px -12px rgba(45, 40, 37, 0.12);
}

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

body {
    font-family: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    padding: 20px;
    -webkit-font-smoothing: antialiased;
}

/* App Container - Minimalist Solid */
.app-container {
    width: 100%;
    max-width: 500px;
    background: var(--app-bg);
    border: 1px solid var(--border-color);
    border-radius: 28px;
    padding: 40px 32px;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    gap: 28px;
    transition: transform 0.3s ease;
}

header {
    text-align: center;
}

.brand-title {
    font-size: 2.75rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 8px;
    letter-spacing: -1px;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
    font-weight: 400;
}

/* Input Area */
.input-group {
    position: relative;
    display: flex;
    align-items: center;
}

#todo-input {
    width: 100%;
    padding: 16px 56px 16px 24px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-primary);
    font-size: 1rem;
    font-family: inherit;
    outline: none;
    transition: all 0.3s ease;
}

#todo-input:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px rgba(193, 110, 90, 0.1);
    background: var(--app-bg);
}

#todo-input::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.add-btn {
    position: absolute;
    right: 8px;
    width: 40px;
    height: 40px;
    border-radius: 12px;
    border: none;
    background: var(--accent-color);
    color: white;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
}

.add-btn:hover {
    background: var(--accent-hover);
    transform: scale(1.05);
}

.add-btn:active {
    transform: scale(0.95);
}

/* Filters */
.filters {
    display: flex;
    justify-content: center;
    gap: 8px;
    background: var(--bg-color);
    padding: 6px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.filter-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.filter-btn.active {
    background: var(--app-bg);
    color: var(--text-primary);
    box-shadow: var(--shadow-sm);
}

/* Todo List */
.todo-list-container {
    max-height: 320px;
    overflow-y: auto;
    padding: 4px;
    margin: -4px;
}

/* Custom Scrollbar */
.todo-list-container::-webkit-scrollbar {
    width: 4px;
}

.todo-list-container::-webkit-scrollbar-track {
    background: transparent;
}

.todo-list-container::-webkit-scrollbar-thumb {
    background: #E6E2D8;
    border-radius: 10px;
}

.todo-list-container::-webkit-scrollbar-thumb:hover {
    background: #D5D0C3;
}

.todo-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.todo-item {
    display: flex;
    align-items: center;
    padding: 16px;
    background: var(--app-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
    animation: slideIn 0.3s ease forwards;
}

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

.todo-item.fadeOut {
    animation: fadeOut 0.3s ease forwards;
}

@keyframes fadeOut {
    from {
        opacity: 1;
        transform: scale(1);
    }
    to {
        opacity: 0;
        transform: scale(0.95);
    }
}

.todo-item:hover {
    background: var(--bg-color);
    border-color: var(--border-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Custom Checkbox */
.checkbox-container {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    border-radius: 8px;
    border: 2px solid #D5D0C3;
    cursor: pointer;
    margin-right: 16px;
    transition: all 0.3s cubic-bezier(0.4, 0.0, 0.2, 1);
    flex-shrink: 0;
    position: relative;
    overflow: hidden;
}

.checkbox-container input {
    display: none;
}

.checkmark {
    position: absolute;
    width: 10px;
    height: 6px;
    border-left: 2px solid white;
    border-bottom: 2px solid white;
    transform: rotate(-45deg) scale(0);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    top: 6px;
}

.todo-item.completed .checkbox-container {
    background: var(--accent-color);
    border-color: var(--accent-color);
}

.todo-item.completed .checkmark {
    transform: rotate(-45deg) scale(1);
    opacity: 1;
}

.todo-text {
    flex-grow: 1;
    font-size: 1rem;
    color: var(--text-primary);
    transition: all 0.3s ease;
    word-break: break-word;
}

.todo-item.completed .todo-text {
    color: var(--text-secondary);
    text-decoration: line-through;
    opacity: 0.6;
}

.delete-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    opacity: 0;
    transform: scale(0.9);
    transition: all 0.3s ease;
    padding: 8px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.todo-item:hover .delete-btn {
    opacity: 1;
    transform: scale(1);
}

.delete-btn:hover {
    color: var(--danger-color);
    background: var(--danger-bg);
}

/* Footer */
.app-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.clear-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    font-family: inherit;
    font-size: 0.875rem;
    transition: color 0.3s ease;
}

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

.empty-state {
    text-align: center;
    padding: 32px 0;
    color: var(--text-secondary);
}

.empty-state svg {
    margin-bottom: 12px;
    opacity: 0.4;
}

@media (max-width: 600px) {
    .app-container {
        padding: 32px 24px;
        border-radius: 24px;
        border-left: none;
        border-right: none;
        box-shadow: none;
        border-radius: 0;
        min-height: 100vh;
    }
    body {
        padding: 0;
        align-items: flex-start;
    }
}