:root {
    --bg: #f4f4f4;
    --text: #2c2c2c;
    --grid-bg: white;
    --wall-bg: #222;
    --lit-bg: #fffbbf;
    --button-bg: #b31b1b;
    --button-hover: #911414;
    --panel-bg: #ffffff;
    --grid-size: 12;
    --cell-size: 40px;
}
html, body {
    max-width: 100%;
    overflow-x: hidden;
}
body.dark {
    --bg: #1c1c1c;
    --text: #f0f0f0;
    --grid-bg: #2a2a2a;
    --wall-bg: #555;
    --lit-bg: #5a5200;
    --button-bg: #e96d6d;
    --button-hover: #cc3f3f;
    --panel-bg: #2c2c2c;
}

body {
    margin: 0;
    padding: 0;
    background: var(--bg);
    color: var(--text);
    transition: background 0.3s, color 0.3s;
    font-family: 'Noto Serif JP', serif;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}
main {
    margin-top: 2rem;
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
h1 {
    color: var(--text);
    text-align: center;
}
a {
    text-decoration: none;
}
.top-right-controls {
    position: absolute;
    top: 1rem;
    right: 1rem;
    display: flex;
    gap: 0.6rem;
    flex-wrap: wrap;
    justify-content: flex-end;
    align-items: center;
    z-index: 20;
}

.toggle-dark {
    background: none;
    color: var(--text);
    border: 1px solid var(--text);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 12px;
    height: 30px;
}

.toggle-dark:hover {
    background: var(--button-bg);
    color: white;
    border-color: var(--button-bg);
}
.lang-toggle {
    background: none;
    color: var(--text);
    border: 1px solid var(--text);
    padding: 0.25rem 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 10;
    height: 30px;
}

.lang-toggle:hover {
    background: var(--button-bg);
    color: white;
    border-color: var(--button-bg);
}

.lang-fade {
    opacity: 0;
    transform: translateY(4px);
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.lang-fade.show {
    opacity: 1;
    transform: translateY(0);
}

.rules-wrapper {
    max-width: 600px;
    margin: 1rem auto 2rem;
    text-align: left;
}

.rules-content {
    background: var(--panel-bg);
    padding: 0 1rem;
    border: 1px solid rgba(0,0,0,0.1);
    border-radius: 6px;
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.4s ease, padding 0.3s ease, background 0.3s;
    color: var(--text);
}

body.dark .rules-content {
    border: 1px solid rgba(255,255,255,0.1);
}

.rules-content.open {
    padding: 1rem;
    max-height: 600px; /* enough space for full expansion */
}

.rules-content ul {
    margin: 0;
    padding-left: 1.2rem;
    list-style-type: none;
}

.rules-content li {
    margin-bottom: 0.5rem;
    line-height: 1.4;
}



#akari-board {
    display: grid;
    grid-template-columns: repeat(var(--grid-size), var(--cell-size));
    grid-template-rows: repeat(var(--grid-size), var(--cell-size));
    gap: 2px;
    margin: 0 auto;
    max-width: 95vw;
}


.lit {
    background: var(--lit-bg);
}

.cell {
    background: var(--grid-bg);
    aspect-ratio: 1 / 1;
    width: var(--cell-size);
    height: var(--cell-size);
    cursor: pointer;
    position: relative;
}

.wall {
    background: var(--wall-bg);
    color: white;
    font-weight: bold;
    display: flex;
    justify-content: center;
    align-items: center;
}
.wall.warn {
    color: #ffd7b5 !important;
}
.wall.error {
    color: red !important;
}

.wall[data-value="1"] {
    color: #66bb6a; /* green */
}

.wall[data-value="2"] {
    color: #ffca28; /* amber */
}

.wall[data-value="3"] {
    color: #ff7043; /* orange */
}

.wall[data-value="4"] {
    color: #ef5350; /* red */
}
body.dark .wall.error { color: red !important; }
body.dark .wall.warn { color: #ffb347 !important; }
body.dark .wall[data-value="1"] { color: #81c784; }
body.dark .wall[data-value="2"] { color: #ffd54f; }
body.dark .wall[data-value="3"] { color: #ff8a65; }
body.dark .wall[data-value="4"] { color: #e57373; }

.cell.bulb {
    background: radial-gradient(circle at center, #fff47a 30%, #ffe680 100%);
    animation: bulbGlow 1.5s infinite ease-in-out;
}

.cell.bulb::after {
    content: "💡";
    position: absolute;
    font-size: 24px;
    top: 4px;
    left: 6px;
}

body.dark .cell.bulb {
    background: radial-gradient(circle at center, #fff99a 30%, #d7b940 100%);
    box-shadow: 0 0 6px rgba(255, 230, 100, 0.6); /* ✨ add this */
    animation: bulbGlow 1.5s infinite ease-in-out;
}

.cell.lit {
    background: linear-gradient(135deg, #fffbbf, #ffe680);
    box-shadow: inset 0 0 4px rgba(255, 240, 120, 0.6),
    0 0 8px rgba(255, 240, 120, 0.3);
    transition: background 0.2s ease, box-shadow 0.2s ease;
}

body.dark .cell.lit {
    background: linear-gradient(135deg, #ffee88, #d6b100);
    box-shadow: inset 0 0 6px rgba(255, 230, 100, 0.4),
    0 0 12px rgba(255, 230, 100, 0.2);
}

/* Bulb Counter Styling */
.bulb-counter {
    position: absolute;
    top: 1rem;
    left: 1rem;
    background: var(--panel-bg);
    color: var(--text);
    border: 1px solid var(--button-bg);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    font-size: 0.95rem;
    font-weight: bold;
    box-shadow: 0 2px 6px rgba(0,0,0,0.1);
    transition: background 0.3s, color 0.3s;
    z-index: 10;
}

body.dark .bulb-counter {
    border-color: var(--button-hover);
}
@keyframes counterPulse {
    0%   { transform: scale(1); }
    50%  { transform: scale(1.3); }
    100% { transform: scale(1); }
}

.bulb-counter.pulse {
    animation: counterPulse 0.25s ease-in-out;
}



/* Error Box Styling */
.error-box {
    max-width: 600px;
    margin: 1rem auto;
    background: var(--panel-bg, #fff);
    border: 1px solid #e0e0e0;
    border-left: 6px solid #b31b1b;
    padding: 1rem 1rem 1rem 1.2rem;
    border-radius: 6px;
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text);
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    opacity: 0;
    max-height: 0;
    overflow: hidden;
    transform: translateY(-10px);
    transition: all 0.4s ease;
}

.error-box ul {
    margin: 0;
    padding: 0;
}

.error-box li {
    list-style: none;
    margin: 0.4rem 0;
}

.error-box.show {
    opacity: 1;
    max-height: 200px;
    transform: translateY(0);
}

body.dark .error-box {
    background: rgba(255, 0, 0, 0.05);
    border-color: rgba(255, 255, 255, 0.15);
}

.action-buttons {
    text-align: center;
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.zen-button {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text);
    border: 1px solid rgba(100, 100, 100, 0.3);
    padding: 0.7rem 1.5rem;
    border-radius: 999px;
    font-size: 1rem;
    font-family: 'Noto Serif JP', serif;
    letter-spacing: 0.5px;
    cursor: pointer;
    transition: all 0.3s ease;
    backdrop-filter: blur(4px);
    box-shadow: inset 0 0 0 transparent;
}

.zen-button:hover {
    background: var(--panel-bg);
    border-color: var(--button-bg);
    color: var(--button-bg);
    box-shadow: inset 0 0 8px rgba(0,0,0,0.05);
}
body.dark .zen-button {
    background: rgba(255, 255, 255, 0.02);
    border-color: rgba(200, 200, 200, 0.1);
}

body.dark .zen-button:hover {
    background: var(--bg);
    border-color: var(--button-hover);
    color: var(--button-hover);
}



/* Individual error types */
.error-box li {
    margin-bottom: 0.4rem;
    line-height: 1.4;
    list-style: none;
    padding-left: 0.2rem;
}

.error-lit {
    color: #b31b1b;
}

.error-conflict {
    color: #e07900;
}

.error-wall {
    color: #0055aa;
}


.error-box.hidden {
    display: none;
}

.cell.error {
    outline: 2px solid red;
    outline-offset: -2px;
}

.cell.warn {
    outline: 2px solid #ffd7b5;
    outline-offset: -2px;
}


.modal {
    position: fixed;
    top: 0; left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
}

.modal.hidden {
    display: none;
}

.modal-content {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    max-width: 300px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.3);
    color: #222;
}
body.dark .modal-content {
    background: #2c2c2c;
    color: #f0f0f0;
    box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
}
.modal-content h2 {
    margin-top: 0;
}
body.dark .modal-content h2 {
    color: #fefefe;
}
body.dark .modal-content p {
    color: #ccc;
}
.modal-content button {
    background: #b31b1b;
    color: white;
    padding: 0.5rem 1rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    margin-top: 1rem;
}
body.dark .modal-content button {
    background: #e96d6d;
}
.modal-content button:hover {
    background: #911414;
}
body.dark .modal-content button:hover {
    background: #cc3f3f;
}

footer {
    margin-top: 3rem;
    padding: 1rem 0;
    font-size: 0.9rem;
    color: #999;
    text-align: center;
}

@keyframes bulbGlow {
    0% {
        box-shadow: 0 0 4px rgba(255, 240, 100, 0.4);
    }
    50% {
        box-shadow: 0 0 10px rgba(255, 240, 100, 0.8);
    }
    100% {
        box-shadow: 0 0 4px rgba(255, 240, 100, 0.4);
    }
}

#akari-board div.cell.wall.error {
    background: #800 !important;
    color: red !important;
    animation: redGlow 1s infinite ease-in-out;
    z-index: 1;
}

@keyframes redGlow {
    0%   { box-shadow: 0 0 0 red; }
    50%  { box-shadow: 0 0 10px red; }
    100% { box-shadow: 0 0 0 red; }
}

#akari-board div.cell.wall.warn {
    background: #ffd7b5 !important;
    color: #ff6700 !important;
    animation: orangeGlow 1s infinite ease-in-out;
    z-index: 1;
}

@keyframes orangeGlow {
    0%   { box-shadow: 0 0 0 #ffd7b5; }
    50%  { box-shadow: 0 0 10px #ffb38a; }
    100% { box-shadow: 0 0 0 #ffd7b5; }
}

@media (max-width: 600px) {
    #akari-board {
        --cell-size: 28px;
    }
    main {
        margin-top: 5.5rem;
    }
    h1 {
        font-size: 1.2rem;
    }
    .cell.bulb::after {
        font-size: 0.9em;
    }
    .top-right-controls {
        justify-content: center;
        width: -webkit-fill-available;
    }
    .bulb-counter {
        font-size: 0.8rem;
        padding: 0.3rem 0.6rem;
        position: relative;
        width: fit-content;
        margin: 0 auto;
        top: -75px;
        left: 0;
    }
    .action-buttons {
        gap: 0.5rem;
    }
    .zen-button {
        padding: 0.5rem 1rem;
        font-size: 0.8rem;
    }

    .modal-content {
        width: 90%;
        padding: 1.2rem;
    }
}