/* ===== Simon Says — Neon Edition ===== */
:root {
    --bg-primary: #060614;
    --bg-card: rgba(15, 15, 35, 0.85);
    --text-primary: #e4e4f0;
    --text-dim: rgba(228, 228, 240, 0.5);
    --neon-green: #00ff88;
    --neon-blue: #00d4ff;
    --neon-pink: #ff2d75;
    --neon-purple: #b44dff;
    --neon-yellow: #ffe600;
    --neon-orange: #ff8a00;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(ellipse at 30% 30%, rgba(0, 255, 136, 0.05) 0%, transparent 50%),
        radial-gradient(ellipse at 70% 70%, rgba(255, 45, 117, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: 0;
}

#app {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 400px;
    padding: 16px 20px 30px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

/* Top Bar */
#top-bar {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#back-link {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.6rem;
    letter-spacing: 0.15em;
    color: var(--neon-green);
    text-decoration: none;
    opacity: 0.8;
    transition: var(--transition);
}

#back-link:hover {
    opacity: 1;
}

#mute-btn {
    background: none;
    border: 1px solid rgba(0, 255, 136, 0.2);
    border-radius: 8px;
    padding: 4px 10px;
    font-size: 0.85rem;
    cursor: pointer;
    color: var(--neon-green);
    font-family: 'Orbitron', sans-serif;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: var(--transition);
}

.mute-label {
    font-size: 0.5rem;
    letter-spacing: 0.1em;
}

/* Header */
#header {
    text-align: center;
}

#title {
    font-family: 'Orbitron', sans-serif;
    font-weight: 900;
    font-size: clamp(1.4rem, 5vw, 2rem);
    letter-spacing: 0.1em;
    background: linear-gradient(135deg, var(--neon-green), var(--neon-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    filter: drop-shadow(0 0 18px rgba(0, 255, 136, 0.3));
}

#subtitle {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.55rem;
    letter-spacing: 0.4em;
    color: var(--text-dim);
    margin-top: 2px;
}

/* Mode and Difficulty selectors */
#mode-selector,
#diff-selector {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    justify-content: center;
}

.mode-btn,
.diff-btn {
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    font-size: 0.5rem;
    letter-spacing: 0.12em;
    padding: 6px 14px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-dim);
    cursor: pointer;
    transition: var(--transition);
}

.mode-btn.active {
    border-color: var(--neon-green);
    color: var(--neon-green);
    background: rgba(0, 255, 136, 0.1);
}

.diff-btn.active {
    border-color: var(--neon-blue);
    color: var(--neon-blue);
    background: rgba(0, 212, 255, 0.1);
}

.mode-btn:hover,
.diff-btn:hover {
    border-color: var(--neon-blue);
    color: var(--neon-blue);
}

.mode-btn.disabled,
.diff-btn.disabled {
    opacity: 0.3;
    pointer-events: none;
}

/* HUD */
#hud {
    display: flex;
    gap: 20px;
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    padding: 10px 24px;
    border-radius: 14px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.hud-item {
    text-align: center;
}

.hud-label {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.4rem;
    letter-spacing: 0.15em;
    color: var(--text-dim);
    display: block;
}

.hud-value {
    font-family: 'Orbitron', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--neon-green);
}

/* Online Panel */
#online-panel {
    background: var(--bg-card);
    backdrop-filter: blur(12px);
    padding: 12px 18px;
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.06);
    text-align: center;
    font-size: 0.65rem;
    width: 100%;
}

.join-row {
    display: flex;
    gap: 6px;
    margin-top: 8px;
    justify-content: center;
}

.join-row input {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.55rem;
    letter-spacing: 0.2em;
    text-align: center;
    text-transform: uppercase;
    padding: 6px 10px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-primary);
    width: 110px;
    outline: none;
}

.join-row input:focus {
    border-color: var(--neon-blue);
}

#room-code {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.9rem;
    color: var(--neon-yellow);
    letter-spacing: 0.15em;
}

#copy-code-btn {
    background: none;
    border: none;
    font-size: 0.9rem;
    cursor: pointer;
    margin-left: 4px;
}

.neon-btn-sm {
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    font-size: 0.45rem;
    letter-spacing: 0.1em;
    padding: 6px 12px;
    border: 1px solid var(--neon-green);
    border-radius: 8px;
    background: rgba(0, 255, 136, 0.08);
    color: var(--neon-green);
    cursor: pointer;
    transition: var(--transition);
}

.neon-btn-sm:hover {
    background: rgba(0, 255, 136, 0.18);
    box-shadow: 0 0 16px rgba(0, 255, 136, 0.2);
}

/* Board — 2x2 grid */
#board {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    width: 260px;
    height: 260px;
}

.simon-btn {
    border-radius: 16px;
    border: 2px solid rgba(255, 255, 255, 0.08);
    cursor: pointer;
    transition: all 0.15s ease;
    outline: none;
}

.simon-btn:active {
    transform: scale(0.95);
}

/* Colors */
#btn-0 {
    background: rgba(0, 255, 136, 0.15);
    border-color: rgba(0, 255, 136, 0.3);
}

#btn-0.lit {
    background: rgba(0, 255, 136, 0.6);
    box-shadow: 0 0 40px rgba(0, 255, 136, 0.5), inset 0 0 20px rgba(0, 255, 136, 0.3);
    border-color: var(--neon-green);
}

#btn-1 {
    background: rgba(255, 45, 117, 0.15);
    border-color: rgba(255, 45, 117, 0.3);
}

#btn-1.lit {
    background: rgba(255, 45, 117, 0.6);
    box-shadow: 0 0 40px rgba(255, 45, 117, 0.5), inset 0 0 20px rgba(255, 45, 117, 0.3);
    border-color: var(--neon-pink);
}

#btn-2 {
    background: rgba(0, 212, 255, 0.15);
    border-color: rgba(0, 212, 255, 0.3);
}

#btn-2.lit {
    background: rgba(0, 212, 255, 0.6);
    box-shadow: 0 0 40px rgba(0, 212, 255, 0.5), inset 0 0 20px rgba(0, 212, 255, 0.3);
    border-color: var(--neon-blue);
}

#btn-3 {
    background: rgba(255, 230, 0, 0.15);
    border-color: rgba(255, 230, 0, 0.3);
}

#btn-3.lit {
    background: rgba(255, 230, 0, 0.6);
    box-shadow: 0 0 40px rgba(255, 230, 0, 0.5), inset 0 0 20px rgba(255, 230, 0, 0.3);
    border-color: var(--neon-yellow);
}

#btn-4 {
    background: rgba(255, 138, 0, 0.15);
    border-color: rgba(255, 138, 0, 0.3);
}

#btn-4.lit {
    background: rgba(255, 138, 0, 0.6);
    box-shadow: 0 0 40px rgba(255, 138, 0, 0.5), inset 0 0 20px rgba(255, 138, 0, 0.3);
    border-color: var(--neon-orange);
}

#btn-5 {
    background: rgba(180, 77, 255, 0.15);
    border-color: rgba(180, 77, 255, 0.3);
}

#btn-5.lit {
    background: rgba(180, 77, 255, 0.6);
    box-shadow: 0 0 40px rgba(180, 77, 255, 0.5), inset 0 0 20px rgba(180, 77, 255, 0.3);
    border-color: var(--neon-purple);
}

/* 6-button Hard mode: 3×2 grid */
#board.board-6 {
    grid-template-columns: 1fr 1fr 1fr;
    width: 360px;
    height: 240px;
}

/* Status */
.status-text {
    font-family: 'Orbitron', sans-serif;
    font-size: 0.6rem;
    letter-spacing: 0.1em;
    color: var(--text-dim);
    text-align: center;
}

/* Button */
.neon-btn {
    font-family: 'Orbitron', sans-serif;
    font-weight: 700;
    font-size: 0.65rem;
    letter-spacing: 0.15em;
    padding: 10px 28px;
    border: 1px solid var(--neon-green);
    border-radius: 10px;
    background: rgba(0, 255, 136, 0.08);
    color: var(--neon-green);
    cursor: pointer;
    transition: var(--transition);
}

.neon-btn:hover {
    background: rgba(0, 255, 136, 0.18);
    box-shadow: 0 0 24px rgba(0, 255, 136, 0.2);
}

.hidden {
    display: none !important;
}

#footer {
    text-align: center;
    font-size: 0.6rem;
    color: var(--text-dim);
    margin-top: 6px;
}

/* Responsive */
@media (max-width: 520px) {

    html,
    body {
        overflow: hidden;
        overscroll-behavior: none;
        touch-action: manipulation;
        position: fixed;
        width: 100%;
        height: 100%;
    }

    body {
        align-items: flex-start;
    }

    #app {
        padding: 6px 8px calc(8px + env(safe-area-inset-bottom, 20px));
        gap: 6px;
        height: 100vh;
        height: 100dvh;
        overflow-y: auto;
        -webkit-overflow-scrolling: touch;
    }

    #board {
        width: min(260px, 70vw);
        height: min(260px, 70vw);
    }

    #board.board-6 {
        width: min(360px, 90vw);
        height: min(240px, 60vw);
    }

    #footer {
        padding-bottom: env(safe-area-inset-bottom, 20px);
        font-size: 0.5rem;
    }
}