* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

html {
    color: #edf2f7;
    font-size: 62.5%;
}

body {
    min-height: 100vh;
    background: radial-gradient(circle at top, rgba(84, 150, 255, 0.22), transparent 30%),
                linear-gradient(180deg, #11151a 0%, #0b1014 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 3rem;
}

.app-shell {
    width: min(100%, 56rem);
}

.app-card {
    background: rgba(17, 23, 31, 0.92);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 2.4rem;
    box-shadow: 0 32px 80px rgba(0, 0, 0, 0.3);
    padding: 3rem;
    backdrop-filter: blur(18px);
}

.app-header {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2.4rem;
}

h1 {
    font-size: 3.6rem;
    letter-spacing: 0.2rem;
    text-transform: uppercase;
}

.app-header p {
    color: #a8b3c0;
    font-size: 1.6rem;
    line-height: 1.6;
    max-width: 44rem;
}

.todo-form {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 1rem;
    margin-bottom: 2.4rem;
}

.todo-form input {
    width: 100%;
    padding: 1.4rem 1.6rem;
    border-radius: 1.2rem;
    border: 1px solid rgba(255, 255, 255, 0.14);
    background: rgba(255, 255, 255, 0.05);
    color: #f7fafc;
    font-size: 1.6rem;
    outline: none;
    transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.todo-form input::placeholder {
    color: rgba(248, 250, 252, 0.65);
}

.todo-form input:focus {
    border-color: #67e8f9;
    box-shadow: 0 0 0 0.2rem rgba(103, 232, 249, 0.18);
}

.btn {
    background: linear-gradient(135deg, #70bfff 0%, #7c77ff 100%);
    border: none;
    border-radius: 1.2rem;
    color: #0b1120;
    font-size: 1.6rem;
    padding: 1.4rem 2rem;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 14px 28px rgba(112, 191, 255, 0.24);
}

.todo-lists-elem {
    display: grid;
    gap: 1rem;
}

.main_todo_div {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    padding: 1.6rem 1.8rem;
    border-radius: 1.6rem;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.main_todo_div li {
    list-style: none;
    font-size: 1.75rem;
    font-weight: 500;
    color: #f8fafc;
    word-break: break-word;
}

.deleteBtn {
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: #f8fafc;
    padding: 1rem 1.4rem;
    border-radius: 1rem;
    cursor: pointer;
    font-size: 1.5rem;
    transition: background 0.25s ease, border-color 0.25s ease;
}

.deleteBtn:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: rgba(255, 255, 255, 0.22);
}

.empty-state {
    margin-top: 1.2rem;
    color: #7c8a9f;
    font-size: 1.5rem;
    text-align: center;
}

@media (max-width: 640px) {
    .app-card {
        padding: 2rem;
    }

    .todo-form {
        grid-template-columns: 1fr;
    }

    .btn {
        width: 100%;
    }

    .main_todo_div {
        flex-direction: column;
        align-items: stretch;
    }

    .deleteBtn {
        width: 100%;
    }
}