.start-secondary {
    width: 100%;
    max-width: 350px;
    margin: 0 auto;
    display: flex;
    justify-content: flex-start;
    align-items: flex-start;
    padding-left: 0.5rem;
    margin-top: -1.2rem;
}

.copyright {
    display: block;
    margin-top: 2.5rem;
    margin-left: 0.2rem;
    font-size: 0.85rem;
    opacity: 0.85;
    pointer-events: none;
    background: none;
    padding: 0;
    border-radius: 0;
    box-shadow: none;
}

.start-copyright {
    color: #4a4a6a;
    margin-top: 2.2rem;
    margin-bottom: 0.2rem;
    font-size: 0.85rem;
    opacity: 0.85;
    display: block;
    text-align: left;
}

.app {
    position: relative;
}

/* Button row for header */
.button-row {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

/* Start screen styles */
.start-screen {
    display: none;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
}

.start-panel {
    background: var(--panel);
    border-radius: 18px;
    box-shadow: 0 8px 32px rgba(25, 20, 65, 0.10);
    padding: 2rem 2.5rem;
    max-width: 350px;
    width: 100%;
    text-align: center;
}

.start-panel h2 {
    margin-top: 0;
    margin-bottom: 1.6rem;
}

.start-panel label {
    display: block;
    margin: 1.1rem 0 0.3rem 0;
    font-weight: 600;
    text-align: left;
}

.start-panel select {
    width: 100%;
    padding: 0.5rem;
    border-radius: 8px;
    border: 1px solid #b0b0c0;
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.start-btn {
    margin-top: 1.5rem;
    width: 100%;
}

:root {
    --bg-1: #f7f4ea;
    --bg-2: #dfe8ff;
    --panel: rgba(255, 255, 255, 0.7);
    --text: #1f1d2e;
    --accent: #0e8f7d;
    --accent-dark: #08695b;
    --warn: #b03a2e;
    --card-back: #173753;
    --card-front: #fffdf6;
    --card-shadow: 0 10px 30px rgba(23, 55, 83, 0.22);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: Arial, Helvetica, sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at 20% 20%, #fff8d9 0%, transparent 36%),
        radial-gradient(circle at 82% 18%, #c3f6ff 0%, transparent 35%),
        linear-gradient(130deg, var(--bg-1), var(--bg-2));
    display: grid;
    place-items: center;
    padding: 1rem;
}

.app {
    width: min(980px, 100%);
    background: var(--panel);
    border: 1px solid rgba(255, 255, 255, 0.7);
    border-radius: 22px;
    /* Fallback for browsers that don't support backdrop-filter */
    background-color: rgba(255, 255, 255, 0.92);
    box-shadow: 0 16px 50px rgba(25, 20, 65, 0.18);
    padding: clamp(1rem, 2vw, 1.6rem);
    animation: rise-in 500ms ease;
}

@supports ((-webkit-backdrop-filter: blur(6px)) or (backdrop-filter: blur(6px))) {
    .app {
        background: var(--panel);
        -webkit-backdrop-filter: blur(6px);
        backdrop-filter: blur(6px);
    }
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.eyebrow {
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: #4a4a6a;
    font-size: 0.75rem;
}

h1 {
    margin: 1rem 0 0;
    font-size: clamp(1.7rem, 3vw, 2.4rem);
}

.btn {
    border: 0;
    border-radius: 999px;
    background: linear-gradient(120deg, var(--accent), #35b58f);
    color: white;
    padding: 0.7rem 1rem;
    font: inherit;
    font-weight: 700;
    cursor: pointer;
    transition: transform 140ms ease, box-shadow 140ms ease;
}

.status-panel {
    margin-top: 1rem;
    display: grid;
    grid-template-columns: repeat(4, minmax(90px, 1fr));
    gap: 0.75rem;
}

.stat-card {
    background: rgba(255, 255, 255, 0.72);
    border-radius: 14px;
    padding: 0.7rem;
    border: 1px solid rgba(90, 95, 130, 0.15);
}

.stat-card p {
    margin: 0;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: #4f4b6f;
}

.stat-card strong {
    display: block;
    margin-top: 0.3rem;
    font-size: 1.3rem;
}

.message {
    margin: 1rem 0;
    font-weight: 600;
    color: var(--accent-dark);
    min-height: 1rem;
}

.message.warn {
    color: var(--warn);
}

.board {
    --columns: 4;
    display: grid;
    grid-template-columns: repeat(var(--columns), 1fr);
    gap: 0.55rem;
    margin-bottom: 0.2rem;
}

.card {
    aspect-ratio: 1 / 1;
    border: 0;
    border-radius: 12px;
    perspective: 1000px;
    background: transparent;
    cursor: pointer;
    padding: 0;
}

.card-face {
    position: absolute;
    inset: 0;
    border-radius: 12px;
    display: grid;
    place-items: center;
    backface-visibility: hidden;
    transition: transform 500ms ease;
    font-size: clamp(2.2rem, 6vw, 4.2rem);
}

.card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 450ms cubic-bezier(0.2, 0.7, 0.1, 1);
    box-shadow: var(--card-shadow);
    border-radius: 12px;
}

.card-back {
    background:
        linear-gradient(145deg, rgba(255, 255, 255, 0.18), transparent),
        linear-gradient(130deg, #1a3f61, var(--card-back));
    color: #e8f0fa;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.card-front {
    background: var(--card-front);
    border: 2px solid rgba(23, 55, 83, 0.2);
    transform: rotateY(180deg);
}

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

.card.matched {
    cursor: default;
}

.card.matched .card-front {
    outline: 3px solid rgba(14, 143, 125, 0.35);
}

@media (max-width: 680px) {
    .status-panel {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .board {
        gap: 0.45rem;
    }
}

@keyframes rise-in {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

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