/* Dublin Core Metadata Explorer
 * =============================
 * Infographic-style flip-card grid of the 15 Dublin Core elements.
 * The #network element is a required empty background layer; all visible
 * content is a sibling overlay so vis-network cannot erase it.
 */

/* ===========================================
   RESET & BASE
   =========================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background-color: aliceblue;
}

/* ===========================================
   CONTAINER & BACKGROUND NETWORK LAYER
   =========================================== */
.container {
    position: relative;
    width: 100%;
    height: 100vh;
}

#network {
    width: 100%;
    height: 100%;
    background-color: aliceblue;
}

/* ===========================================
   TITLE (Top Center)
   =========================================== */
.title {
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    font-size: 20px;
    font-weight: bold;
    color: #0d3b66;
    background-color: aliceblue;
    padding: 4px 12px;
    white-space: nowrap;
    z-index: 10;
}

/* ===========================================
   PROGRESS BADGE (Upper Right)
   =========================================== */
.progress-badge {
    position: absolute;
    top: 12px;
    right: 12px;
    background-color: #0d3b66;
    color: #ffffff;
    font-size: 13px;
    font-weight: bold;
    padding: 6px 12px;
    border-radius: 14px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
    z-index: 20;
}

.progress-badge.complete {
    background-color: #2e7d32;
}

/* ===========================================
   CONTENT OVERLAY (scrolls inside the frame)
   =========================================== */
.content-overlay {
    position: absolute;
    top: 46px;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 10;
    overflow-y: auto;
    padding: 8px 16px 16px 16px;
}

.subtitle {
    text-align: center;
    font-size: 13px;
    color: #33475b;
    max-width: 760px;
    margin: 4px auto 14px auto;
    line-height: 1.5;
}

/* ===========================================
   FLIP-CARD GRID (5 x 3 -> reflows to 3 x 5)
   =========================================== */
.grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 12px;
    max-width: 900px;
    margin: 0 auto;
}

/* Each card is a perspective container so the inner face can rotate in 3D */
.card {
    perspective: 900px;
    height: 118px;
    cursor: pointer;
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.5s;
    transform-style: preserve-3d;
}

.card.flipped .card-inner {
    transform: rotateY(180deg);
}

.card-face {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    border-radius: 10px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.12);
    display: flex;
    flex-direction: column;
    padding: 10px;
    overflow: hidden;
}

/* FRONT: element name on a blue tile */
.card-front {
    background: linear-gradient(160deg, #2f6fb0 0%, #1f5c9e 100%);
    color: #ffffff;
    align-items: center;
    justify-content: center;
    text-align: center;
    border: 2px solid #17456f;
}

.card-front .element-name {
    font-size: 17px;
    font-weight: bold;
    letter-spacing: 0.3px;
}

.card-front .element-tap {
    font-size: 10px;
    margin-top: 6px;
    opacity: 0.85;
}

/* Hover highlight to signal interactivity (only while not yet flipped) */
.card:not(.flipped):hover .card-front {
    background: linear-gradient(160deg, #3a80c6 0%, #2a6bb2 100%);
    border-color: #ffd54f;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.22);
}

/* Explored/checkmark badge on the front once a card has been opened */
.card.explored .card-front::after {
    content: "\2713";
    position: absolute;
    top: 5px;
    right: 7px;
    font-size: 13px;
    font-weight: bold;
    color: #0d3b66;
    background: #ffd54f;
    width: 20px;
    height: 20px;
    line-height: 20px;
    text-align: center;
    border-radius: 50%;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* BACK: definition + example value */
.card-back {
    background-color: #ffffff;
    color: #1c2b3a;
    transform: rotateY(180deg);
    border: 2px solid #2f6fb0;
    justify-content: flex-start;
}

.card-back .back-name {
    font-size: 12px;
    font-weight: bold;
    color: #1f5c9e;
    margin-bottom: 3px;
}

.card-back .back-def {
    font-size: 10px;
    line-height: 1.35;
    color: #40566b;
    margin-bottom: 5px;
}

.card-back .back-example-label {
    font-size: 9px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #8a99a8;
}

.card-back .back-example {
    font-size: 10.5px;
    font-weight: bold;
    color: #0d3b66;
    line-height: 1.3;
    word-break: break-word;
}

/* ===========================================
   FOOTER CONTROLS
   =========================================== */
.footer-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 14px;
    margin: 18px auto 4px auto;
    flex-wrap: wrap;
}

.footer-hint {
    font-size: 12px;
    color: #607890;
}

.btn {
    padding: 8px 18px;
    font-size: 13px;
    font-weight: bold;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-secondary {
    background-color: #607890;
    color: white;
}

.btn-secondary:hover {
    background-color: #4d6379;
}

/* ===========================================
   RESPONSIVE: reflow to 3 columns on narrow screens
   =========================================== */
@media (max-width: 640px) {
    .title {
        font-size: 16px;
    }
    .grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 9px;
    }
    .card {
        height: 108px;
    }
    .card-front .element-name {
        font-size: 14px;
    }
    .progress-badge {
        font-size: 11px;
        padding: 5px 9px;
    }
}

@media (max-width: 380px) {
    .grid {
        grid-template-columns: repeat(2, 1fr);
    }
}