@import url('https://fonts.googleapis.com/css2?family=Exo+2:wght@400;700;800&family=Lato:wght@300;400;700&display=swap');

:root {
    --bg-deep: #030307;
    --card-bg: rgba(20, 22, 30, 0.4);
    --card-border: rgba(255, 255, 255, 0.08);
    --primary-accent: #00f0ff;
    --secondary-accent: #7000ff;
    --text-main: #f8fafc;
    --glass-blur: blur(20px);
    --neon-glow: 0 0 30px rgba(0, 240, 255, 0.25);
}

body, html {
    margin: 0; padding: 0;
    font-family: 'Lato', sans-serif;
    background-color: var(--bg-deep);
    color: var(--text-main);
    min-height: 100vh;
    display: flex; justify-content: center; align-items: center;
    overflow-x: hidden; position: relative;
}

body::before, body::after {
    content: ''; position: fixed;
    width: 50vw; height: 50vw; border-radius: 50%;
    filter: blur(120px); z-index: 0; opacity: 0.4;
    pointer-events: none;
    animation: floatOrb 20s infinite alternate ease-in-out;
}
body::before { background: radial-gradient(circle, var(--secondary-accent) 0%, transparent 70%); top: -20%; left: -10%; }
body::after { background: radial-gradient(circle, var(--primary-accent) 0%, transparent 70%); bottom: -20%; right: -10%; animation-delay: -10s; }

@keyframes floatOrb {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(10%, 10%) scale(1.2); }
}

.game-container {
    display: flex; flex-direction: row; gap: 40px; padding: 20px;
    width: 100%; max-width: 1200px; box-sizing: border-box; flex-wrap: wrap;
    position: relative; z-index: 1; align-items: center; justify-content: center;
}

#board {
    width: 90vmin; height: 90vmin; max-width: 680px; max-height: 680px;
    aspect-ratio: 1/1; display: grid; grid-template-columns: repeat(8, 1fr); grid-template-rows: repeat(8, 1fr);
    background-image: url('assets/board.png'); background-size: cover;
    border: 2px solid var(--card-border);
    border-radius: 12px;
    box-shadow: 0 25px 60px rgba(0,0,0,0.8), var(--neon-glow);
    flex-shrink: 0; position: relative; overflow: hidden;
    transition: box-shadow 0.3s ease, border-color 0.3s ease;
}

#board:hover {
    border-color: rgba(0, 240, 255, 0.5);
    box-shadow: 0 25px 60px rgba(0,0,0,0.9), 0 0 40px rgba(0, 240, 255, 0.4);
}

.square {
    display: flex; justify-content: center; align-items: center; position: relative;
    background-size: 85%; background-repeat: no-repeat; background-position: center;
    transition: background-color 0.2s ease;
}
.square:hover { cursor: pointer; }

.wp, .wn, .wb, .wr, .wq, .wk, .bp, .bn, .bb, .br, .bq, .bk {
    filter: drop-shadow(0 6px 10px rgba(0,0,0,0.7)); 
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), filter 0.3s ease;
}
.square:hover [class*="w"], .square:hover [class*="b"] { 
    transform: scale(1.1) translateY(-3px); 
    filter: drop-shadow(0 10px 15px rgba(0,0,0,0.8));
}

.wp { background-image: url('assets/wp.png'); } .wn { background-image: url('assets/wn.png'); } .wb { background-image: url('assets/wb.png'); } .wr { background-image: url('assets/wr.png'); } .wq { background-image: url('assets/wq.png'); } .wk { background-image: url('assets/wk.png'); }
.bp { background-image: url('assets/bp.png'); } .bn { background-image: url('assets/bn.png'); } .bb { background-image: url('assets/bb.png'); } .br { background-image: url('assets/br.png'); } .bq { background-image: url('assets/bq.png'); } .bk { background-image: url('assets/bk.png'); }

.square.highlight-selected { background-color: rgba(0, 240, 255, 0.35) !important; box-shadow: inset 0 0 20px var(--primary-accent) !important; }
.square.highlight-last { background-color: rgba(112, 0, 255, 0.35) !important; }
.square.highlight-check { background-color: rgba(255, 0, 85, 0.6) !important; box-shadow: inset 0 0 30px rgba(255, 0, 85, 0.9) !important; }

.highlight-valid::after { 
    content: ''; position: absolute; width: 25%; height: 25%; 
    background: var(--primary-accent); border-radius: 50%; opacity: 0.6; 
    box-shadow: 0 0 15px var(--primary-accent); pointer-events: none; 
}

.side-panel { display: flex; flex-direction: column; gap: 25px; width: 300px; flex-shrink: 0; }

#info-panel, #controls-panel {
    background: var(--card-bg); backdrop-filter: var(--glass-blur); -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--card-border); border-radius: 20px; padding: 25px; 
    box-shadow: 0 20px 40px rgba(0,0,0,0.6); position: relative; overflow: hidden;
}

#info-panel::before, #controls-panel::before {
    content: ''; position: absolute; top: 0; left: -100%; width: 50%; height: 100%;
    background: linear-gradient(to right, transparent, rgba(255,255,255,0.03), transparent);
    transform: skewX(-20deg); transition: 0.7s ease;
}
#info-panel:hover::before, #controls-panel:hover::before { left: 150%; }

#info-panel { 
    font-size: 1.15em; font-family: 'Exo 2', sans-serif; text-align: center; 
    text-transform: uppercase; letter-spacing: 1px; color: var(--primary-accent); 
    text-shadow: 0 0 10px rgba(0,240,255,0.4); line-height: 1.8;
}

#controls-panel h3 { 
    font-family: 'Exo 2', sans-serif; margin: 0 0 15px 0; font-size: 1.3em; text-align: center; text-transform: uppercase; 
    background: linear-gradient(135deg, #fff, var(--primary-accent)); 
    -webkit-background-clip: text; 
    background-clip: text; 
    -webkit-text-fill-color: transparent; 
    border-bottom: 1px solid var(--card-border); padding-bottom: 12px; letter-spacing: 2px;
}

.control-group { display: flex; justify-content: space-between; align-items: center; margin-bottom: 25px; }

#depth-selector, #time-selector { 
    width: 70px; padding: 10px; background: rgba(0,0,0,0.5); color: #fff; 
    border: 1px solid var(--card-border); border-radius: 8px; font-family: inherit; font-size: 1em; 
    text-align: center; outline: none; transition: all 0.3s ease; 
}
#depth-selector:focus, #time-selector:focus { border-color: var(--primary-accent); box-shadow: inset 0 0 10px rgba(0,240,255,0.2); }

#start-game-btn {
    width: 100%; padding: 15px; background: linear-gradient(45deg, rgba(0,240,255,0.1), rgba(112,0,255,0.1));
    color: #fff; border: 1px solid var(--primary-accent); border-radius: 50px; 
    font-family: 'Exo 2', sans-serif; text-transform: uppercase; font-weight: bold; font-size: 1em;
    cursor: pointer; transition: all 0.3s ease; position: relative; overflow: hidden; z-index: 1; letter-spacing: 2px;
}
#start-game-btn::before { 
    content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 100%; 
    background: linear-gradient(45deg, var(--primary-accent), var(--secondary-accent)); 
    z-index: -1; opacity: 0; transition: opacity 0.3s ease; 
}
#start-game-btn:hover::before { opacity: 1; }
#start-game-btn:hover { box-shadow: 0 0 25px rgba(0,240,255,0.6); transform: scale(1.03); border-color: transparent; }

#promotion-choice { 
    position: absolute; background: rgba(10, 12, 18, 0.95); backdrop-filter: var(--glass-blur); 
    border: 1px solid var(--primary-accent); padding: 15px; border-radius: 16px; 
    box-shadow: 0 15px 50px rgba(0,0,0,0.9), 0 0 20px rgba(0,240,255,0.3); z-index: 2000; gap: 12px; 
}
.promotion-button { 
    width: 70px; height: 70px; border-radius: 12px; background-color: rgba(255,255,255,0.03); 
    border: 1px solid var(--card-border); transition: all 0.3s ease; 
    background-size: 85%; background-repeat: no-repeat; background-position: center; cursor: pointer;
}
.promotion-button:hover { 
    background-color: rgba(0,240,255,0.2); border-color: var(--primary-accent); 
    transform: translateY(-5px) scale(1.05); box-shadow: 0 5px 15px rgba(0,240,255,0.4); 
}

@media (max-width: 1000px) { 
    body, html { display: block; min-height: auto; padding-bottom: 30px; } 
    .game-container { flex-direction: column; padding: 15px; } 
    .side-panel { width: 90vmin; max-width: 680px; flex-direction: row; flex-wrap: wrap; } 
    #info-panel, #controls-panel { flex: 1; min-width: 280px; } 
}
@media (max-width: 600px) { 
    .side-panel { flex-direction: column; } 
    .promotion-button { width: 55px; height: 55px; } 
}