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

html, body {
    height: 100%;
    width: 100%;
}

html {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

:root {
    --bg-color: #000;
    --primary-text-color: #f4f4f4;
    --bg-btn-color: #1a1a1a;
    --bg-task-color: #2a2a2a;
    --bg-delete-color: #ff4d4d;

    /* padding variables */
    --nav-padding: 15px 30px;
    --section-padding: 15px 30px;
    --padding-s: 5px;
    --padding-m: 10px;
    --padding-l: 15px;
    --padding-xl: 20px;
    --padding-xxl: 30px;

    /* border-radius variables */
    --border-radius-s: 5px;
    --border-radius-m: 10px;
    --border-radius-l: 15px;
    --border-radius-xl: 20px;
    --border-radius-xxl: 30px;
}

body {
    background-color: var(--bg-color);
    color: var(--primary-text-color);
}

main {
    height: 100%;
    display: flex;
    flex-direction: column;
}

nav {
    padding: var(--nav-padding);
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    background-color: var(--bg-color);
    backdrop-filter: blur(5px);
}

nav button {
    background-color: var(--bg-btn-color);
    border: none;
    outline: none;
    color: var(--primary-text-color);
    padding: var(--padding-m) var(--padding-l);
    cursor: pointer;
    border-radius: var(--border-radius-m);
}

section {
    padding: var(--section-padding);
    display: flex;
    flex-grow: 1;
    justify-content: space-between;
    gap: var(--padding-xxl);
}

section .task-column {
    background-color: var(--bg-btn-color);
    flex-grow: 1;
    width: 100%;
    padding: var(--padding-m);
    display: flex;
    flex-direction: column;
    gap: var(--padding-m);
    border-radius: var(--border-radius-m);
    transition: all 0.7s cubic-bezier(0.19, 1, 0.22, 1);
}

section .task-column.hover-over {
    border: 2px dashed var(--primary-text-color);
    scale: 1.05;
}

section .task-column .heading {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

section .task-column .task {
    background-color: var(--bg-task-color);
    padding: var(--padding-m);
    border-radius: var(--border-radius-m);
    display: flex;
    flex-direction: column;
    gap: var(--padding-s);
    cursor: grab;
}

section .task-column .task button {
    align-self: flex-end;
    cursor: pointer;
    padding: var(--padding-s) var(--padding-m);
    border-radius: var(--border-radius-s);
    border: none;
    outline: none;
    background-color: var(--bg-delete-color);
    color: var(--primary-text-color);
}


@media (max-width: 768px) {

    :root {
        --nav-padding: 10px 15px;
        --section-padding: 10px 15px;
    }

    nav {
        flex-direction: column;
        gap: var(--padding-m);
        align-items: flex-start;
    }

    nav .right {
        width: 100%;
    }

    nav button {
        width: 100%;
        text-align: center;
    }

    section {
        flex-direction: column;
        gap: var(--padding-l);
    }

    section .task-column {
        width: 100%;
        scale: 1;
    }

    section .task-column.hover-over {
        scale: 1.02;
    }

    .modal .center {
        width: 90%;
        padding: var(--padding-l);
    }

    .modal .center input,
    .modal .center textarea {
        width: 100%;
    }

    .modal .center textarea {
        min-height: 100px;
        resize: vertical;
    }
}

@media (max-width: 480px) {

    nav .left {
        font-size: 1.1rem;
        font-weight: 600;
    }

    section .task-column .heading {
        font-size: 0.95rem;
    }

    section .task-column .task {
        padding: var(--padding-s);
    }

    section .task-column .task button {
        font-size: 0.8rem;
        padding: 4px 8px;
    }
}


.modal {
    position: fixed;
    height: 100vh;
    width: 100vw;
    top: 0;
    left: 0;
    display: none;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal .bg {
    position: absolute;
    height: 100%;
    width: 100%;
    background-color: rgba(20, 20, 20, 0.247);
    backdrop-filter: blur(5px);
}

.modal .center {
    background-color: var(--bg-btn-color);
    padding: var(--padding-xxl);
    border-radius: var(--border-radius-m);
    display: flex;
    flex-direction: column;
    gap: var(--padding-m);
    z-index: 10;
}

.modal .center input, .modal .center textarea, .modal .center select {
    background-color: var(--bg-task-color);
    border: none;
    outline: none;
    color: var(--primary-text-color);
    padding: var(--padding-m);
    border-radius: var(--border-radius-s);
}

.modal .center button {
    background-color: var(--bg-task-color);
    border: none;
    outline: none;
    color: var(--primary-text-color);
    padding: var(--padding-m) var(--padding-l);
    cursor: pointer;
    border-radius: var(--border-radius-m);
    width: fit-content;
    align-self: center;
}