:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-dim: #94a3b8;
    --accent: #10b981;
    --danger: #ef4444;
    --radius: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Outfit', sans-serif;
    background: var(--bg-gradient);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding-top: 5rem;
    overflow-x: hidden;
    position: relative;
}

/* Background Blobs */
.background-blobs {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    filter: blur(80px);
}

.blob {
    position: absolute;
    border-radius: 50%;
    opacity: 0.4;
}

.blob-1 {
    width: 400px;
    height: 400px;
    background: var(--primary);
    top: -10%;
    left: -10%;
    animation: move 20s infinite alternate;
}

.blob-2 {
    width: 300px;
    height: 300px;
    background: #a855f7;
    bottom: 10%;
    right: -5%;
    animation: move 25s infinite alternate-reverse;
}

.blob-3 {
    width: 250px;
    height: 250px;
    background: #06b6d4;
    top: 40%;
    left: 60%;
    animation: move 18s infinite alternate;
}

@keyframes move {
    from {
        transform: translate(0, 0);
    }

    to {
        transform: translate(100px, 50px);
    }
}

/* App Container */
.app-container {
    width: 100%;
    max-width: 500px;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 2.5rem;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    animation: slideUp 0.6s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

h1 {
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: -2px;
    background: linear-gradient(to right, #fff, var(--text-dim));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
}

.subtitle {
    color: var(--text-dim);
    font-size: 1rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    font-weight: 500;
}

/* Input Section */
.input-wrapper {
    position: relative;
    display: flex;
    gap: 12px;
    margin-bottom: 2rem;
}

input[type="text"] {
    flex: 1;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    padding: 1rem 1.5rem;
    color: #fff;
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
}

input[type="text"]:focus {
    outline: none;
    border-color: var(--primary);
    background: rgba(255, 255, 255, 0.08);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.2);
}

#add-btn {
    background: var(--primary);
    color: white;
    border: none;
    border-radius: var(--radius);
    width: 52px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
}

#add-btn:hover {
    background: var(--primary-hover);
    transform: scale(1.05);
}

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

/* Filters */
.filters {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-bottom: 1.5rem;
}

.filter-btn {
    background: transparent;
    border: 1px solid var(--glass-border);
    color: var(--text-dim);
    padding: 0.5rem 1rem;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 500;
    transition: var(--transition);
}

.filter-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-main);
}

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

/* Todo List */
ul {
    list-style: none;
    margin-bottom: 1.5rem;
}

.todo-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 1rem;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    margin-bottom: 12px;
    transition: var(--transition);
    animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateX(-10px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.todo-item:hover {
    background: rgba(255, 255, 255, 0.06);
    transform: translateX(4px);
}

.todo-item.completed {
    opacity: 0.6;
}

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

.checkbox-custom {
    width: 24px;
    height: 24px;
    border: 2px solid var(--glass-border);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    color: transparent;
}

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

.todo-text {
    flex: 1;
    font-size: 1rem;
    font-weight: 400;
}

.delete-btn {
    background: transparent;
    border: none;
    color: var(--text-dim);
    cursor: pointer;
    padding: 4px;
    border-radius: 8px;
    transition: var(--transition);
    opacity: 0;
}

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

.delete-btn:hover {
    color: var(--danger);
    background: rgba(239, 68, 68, 0.1);
}

/* Stats Footer */
.todo-stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1.5rem;
    border-top: 1px solid var(--glass-border);
    font-size: 0.85rem;
    color: var(--text-dim);
}

#clear-completed {
    background: transparent;
    border: none;
    color: var(--text-dim);
    cursor: pointer;
    font-family: inherit;
    transition: var(--transition);
}

#clear-completed:hover {
    color: var(--danger);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 2rem 0;
    color: var(--text-dim);
}

.empty-state svg {
    margin-bottom: 1rem;
    opacity: 0.3;
}