:root {
    --bg-color: #2b2b2b; /* Dark grey */
    --menu-bg: #333333;
    --text-outline: #000080; /* Dark blue outline */
    --btn-color: #ff8c00; /* Vibrant Orange */
    --btn-hover: #e07b00;
    --cell-bg: #444444;
}

html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    min-height: 100vh; /* Allows expansion */
    overflow-y: auto; /* Allows scrolling on the Y axis if content doesn't fit */
    overflow-x: hidden; /* Prevents horizontal scrolling */
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-color);
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Base Text Styling - Explicitly zeroing out webkit-stroke to prevent smudges globally */
h1, h2, h3, .btn, .mode-btn, .start-btn, .back-btn, .top-btn, .cell {
    color: white;
    -webkit-text-stroke: 0px transparent !important; 
    text-shadow: 
        -1px -1px 0 var(--text-outline),  
         1px -1px 0 var(--text-outline),
        -1px  1px 0 var(--text-outline),
         1px  1px 0 var(--text-outline),
         2px 2px 4px rgba(0,0,0,0.6);
}

/* Portrait Warning Banner */
#portrait-warning {
    display: none; /* Hidden by default */
    width: 100%;
    background-color: #d32f2f;
    color: white;
    text-align: center;
    padding: 10px 5px;
    font-weight: bold;
    font-size: 1.1rem;
    z-index: 1000;
    text-shadow: none;
}

@media screen and (orientation: portrait) {
    #portrait-warning {
        display: block;
    }
}

/* Top Navigation Bar */
#top-bar {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    box-sizing: border-box;
    background: rgba(0, 0, 0, 0.3);
    gap: 10px;
}

.top-btn {
    background-color: var(--btn-color);
    border: 2px solid var(--text-outline);
    /* Responsive sizing: dynamically shrinks on small screens to prevent overlapping */
    padding: clamp(8px, 2vw, 12px) clamp(10px, 3vw, 20px);
    font-size: clamp(0.9rem, 3.5vw, 1.4rem); 
    font-weight: 800;
    border-radius: 6px;
    cursor: pointer;
    text-align: center;
}

/* Main Container */
.container {
    text-align: center;
    width: 100%;
    max-width: 600px;
    padding: 10px;
    box-sizing: border-box;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    margin: 0 auto;
}

#main-title {
    font-size: clamp(1.8rem, 5vw, 2.5rem);
    margin: 5px 0 15px 0;
}

/* Menu Styles */
.menu-card {
    background: var(--menu-bg);
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.5);
    border: 2px solid var(--text-outline);
    width: 100%;
    box-sizing: border-box;
}

.setup-details {
    margin-top: 15px;
}

input[type="text"] {
    width: 90%;
    padding: 12px;
    margin: 10px 0;
    font-size: 1.2rem;
    border-radius: 6px;
    border: 2px solid var(--text-outline);
    background: #555;
    color: white;
    text-align: center;
}

input::placeholder {
    color: #ccc;
}

.button-group {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-top: 15px;
}

.btn, .mode-btn, .start-btn, .back-btn {
    background-color: var(--btn-color);
    border: 2px solid var(--text-outline);
    padding: 15px 20px;
    font-size: 1.4rem; 
    font-weight: 900;  
    letter-spacing: 2px; 
    border-radius: 8px;
    cursor: pointer;
    transition: transform 0.1s, filter 0.2s;
    width: 100%;
    box-sizing: border-box;
}

.btn:active, .mode-btn:active, .start-btn:active, .top-btn:active {
    transform: scale(0.95);
    filter: brightness(0.9);
}

.btn-secondary {
    background-color: #666;
    margin-top: 10px;
}

.hidden {
    display: none !important;
}

/* Responsive Board Styles */
#board-container {
    position: relative;
    width: min(85vw, 50vh); 
    height: min(85vw, 50vh);
    margin: 10px auto 20px auto;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    grid-gap: 5px;
    background-color: var(--text-outline);
    border: 5px solid var(--text-outline);
    border-radius: 8px;
    box-sizing: border-box;
    width: 100%;
    height: 100%;
}

.cell {
    background: var(--cell-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: min(20vw, 12vh); 
    font-weight: bold;
    cursor: pointer;
    transition: background 0.2s;
}

.cell:active {
    background: #666666;
}

.piece {
    pointer-events: none;
}

/* Pause Overlay */
#pause-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 20;
    border-radius: 8px;
}

/* Win Line Overlay */
#win-line-container {
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    pointer-events: none;
    z-index: 10;
    clip-path: polygon(0 0, 0 0, 0 100%, 0 100%);
    animation: revealLine 0.6s ease-in-out forwards;
}

@keyframes revealLine {
    to { clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%); }
}

#win-line-svg {
    width: 100%;
    height: 100%;
    filter: drop-shadow(0px 0px 6px rgba(0,0,0,0.9));
}

#win-line {
    stroke: #ffeb3b; 
}