:root {
    --neon-blue: #00e0ff;
    --neon-pink: #ff00ff;
    --dark-bg: #070710;
    --mid-bg: #1a1a2e;
    --light-text: #f0f0f5;
    --transition-speed: 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--dark-bg);
    color: var(--light-text);
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-image: radial-gradient(circle at center, rgba(13, 20, 40, 0.4) 0%, rgba(13, 20, 40, 0) 70%);
}

.container {
    background: var(--mid-bg);
    padding: 50px 40px;
    border-radius: 12px;
    box-shadow: 
        0 0 30px rgba(0, 224, 255, 0.6),
        0 0 60px rgba(255, 0, 255, 0.3),
        inset 0 0 10px rgba(0, 224, 255, 0.1);
    width: 90%;
    max-width: 480px;
    border: 1px solid rgba(0, 224, 255, 0.2);
}

h1 {
    text-align: center;
    color: var(--neon-blue);
    text-shadow: 0 0 8px var(--neon-blue), 0 0 15px rgba(0, 224, 255, 0.5);
    margin-bottom: 35px;
    letter-spacing: 3px;
    font-size: 2.2em;
    text-transform: uppercase;
}

#taskInput {
    width: calc(100% - 165px); 
    padding: 14px;
    margin-right: 15px; 
    border: 2px solid var(--neon-pink);
    border-radius: 6px;
    background: #252538;
    color: var(--light-text);
    box-shadow: 0 0 10px rgba(255, 0, 255, 0.6), inset 0 0 5px rgba(0, 0, 0, 0.5);
    transition: all var(--transition-speed) ease;
    display: inline-block; 
}

#taskInput::placeholder {
    color: rgba(255, 255, 255, 0.4);
}

#taskInput:focus {
    outline: none;
    border-color: var(--neon-blue);
    box-shadow: 0 0 15px var(--neon-blue);
}

#addTaskBtn {
    padding: 14px 20px;
    background-color: var(--neon-pink);
    color: var(--dark-bg);
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-weight: bold;
    text-transform: uppercase;
    box-shadow: 0 0 10px var(--neon-pink), 0 0 20px rgba(255, 0, 255, 0.4);
    transition: all var(--transition-speed) ease;
    display: inline-block;
}

#addTaskBtn:hover {
    background-color: var(--neon-blue);
    box-shadow: 0 0 15px var(--neon-blue), 0 0 25px rgba(0, 224, 255, 0.6);
    transform: translateY(-2px);
}

#taskList {
    list-style: none;
    padding: 0;
    margin-top: 25px;
}

#taskList li {
    display: flex;
    align-items: center;
    padding: 18px 15px;
    margin-bottom: 12px;
    background: rgba(40, 40, 60, 0.4);
    border-radius: 6px;
    border-left: 6px solid var(--neon-blue);
    transition: all var(--transition-speed) ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    position: relative;
    overflow: hidden;
}

#taskList li:hover {
    background: rgba(40, 40, 60, 0.7);
    transform: translateX(5px);
    box-shadow: 0 0 12px rgba(0, 224, 255, 0.5);
}

#taskList li input[type="checkbox"] {
    appearance: none;
    width: 22px;
    height: 22px;
    border: 3px solid var(--neon-pink);
    border-radius: 50%;
    margin-right: 20px;
    cursor: pointer;
    background: transparent;
    transition: all var(--transition-speed) ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

#taskList li input[type="checkbox"]:checked {
    border-color: var(--neon-blue);
    background-color: var(--neon-blue);
    box-shadow: 0 0 10px var(--neon-blue);
    transform: scale(1.1);
}

#taskList li input[type="checkbox"]:checked::after {
    content: '✓';
    color: var(--dark-bg);
    font-size: 16px;
    font-weight: 900;
}

#taskList li span {
    flex-grow: 1;
    font-size: 1.1em;
}

.done {
    text-decoration: line-through;
    color: #555555 !important;
    border-left: 6px solid var(--neon-pink) !important; 
    box-shadow: none !important;
    opacity: 0.5;
    transition: all var(--transition-speed) ease;
}

#taskList li button {
    background: none;
    border: 2px solid var(--neon-pink);
    color: var(--neon-pink);
    padding: 8px 15px;
    margin-left: 15px;
    border-radius: 4px;
    cursor: pointer;
    text-transform: uppercase;
    font-weight: 600;
    transition: all var(--transition-speed) ease;
}

#taskList li button:hover {
    background-color: var(--neon-pink);
    color: var(--dark-bg);
    box-shadow: 0 0 10px var(--neon-pink);
}