:root {
    --bg-color: #000000;
    --text-main: #ffffff;
    --text-muted: #888888;
    --btn-bg: #ffffff;
    --btn-text: #000000;
    --btn-hover: #cccccc;
    --glass-bg: rgba(0, 0, 0, 0.1);
    --glass-border: rgba(255, 255, 255, 0.1);
    --modal-bg: rgba(0, 0, 0, 0.6);
    --msg-bg: rgba(255, 255, 255, 0.1);
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --text-main: #000000;
    --text-muted: #666666;
    --btn-bg: #000000;
    --btn-text: #ffffff;
    --btn-hover: #333333;
    --glass-bg: rgba(255, 255, 255, 0.1);
    --glass-border: rgba(0, 0, 0, 0.1);
    --modal-bg: rgba(255, 255, 255, 0.6);
    --msg-bg: rgba(0, 0, 0, 0.05);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    position: relative;
    transition: background-color 0.3s;
}

/* Fluid Background Canvas */
#fluid-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: 0;
    pointer-events: none;
}

/* Glassmorphism Container */
.glass-container {
    position: relative;
    z-index: 10;
    background: var(--glass-bg);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 40px;
    width: 90%;
    max-width: 450px;
    text-align: center;
    transition: all 0.3s ease;
    animation: popupCard 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
    transform: scale(0.5);
    opacity: 0;
}

@keyframes popupCard {
    to {
        transform: scale(1);
        opacity: 1;
    }
}

h1 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 10px;
    color: var(--text-main);
}

p {
    color: var(--text-muted);
    margin-bottom: 20px;
    font-size: 1rem;
}

/* Inputs & Buttons */
input[type="number"] {
    width: 100%;
    padding: 15px;
    background: var(--glass-bg);
    border: 2px solid var(--glass-border);
    border-radius: 12px;
    color: var(--text-main);
    font-size: 1.5rem;
    text-align: center;
    outline: none;
    transition: border-color 0.3s;
    margin-bottom: 20px;
}

input[type="number"]:focus {
    border-color: var(--btn-bg);
}

/* Hide arrows from number input */
input[type="number"]::-webkit-inner-spin-button, 
input[type="number"]::-webkit-outer-spin-button { 
    -webkit-appearance: none; 
    margin: 0; 
}

.btn {
    background: var(--btn-bg);
    color: var(--btn-text);
    border: none;
    padding: 15px 30px;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    width: 100%;
    transition: all 0.3s ease;
}

.btn:hover {
    background: var(--btn-hover);
    transform: translateY(-2px);
}

.btn:active {
    transform: translateY(1px);
}

/* Status & Info */
.stats-container {
    display: flex;
    justify-content: space-between;
    margin-bottom: 20px;
    padding: 15px;
    background: var(--glass-bg);
    border-radius: 12px;
    font-weight: 600;
}

.stat-item span {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-item strong {
    font-size: 1.2rem;
    color: var(--text-main);
}

.message {
    margin: 15px 0;
    padding: 12px;
    border-radius: 8px;
    font-weight: 600;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    background: var(--msg-bg);
    color: var(--text-main);
    border: 1px solid var(--glass-border);
}

.message.show {
    opacity: 1;
    transform: translateY(0);
}

/* Screens */
.screen {
    display: none;
    animation: fadeIn 0.4s ease-out forwards;
}

.screen.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

/* Confetti Canvas for winning */
#confetti {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 100;
}

/* Top Navbar */
.top-navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    margin-bottom: 25px;
}

.top-btns-right {
    display: flex;
    gap: 10px;
}

.btn-icon {
    width: 35px;
    height: 35px;
    border-radius: 50%;
    background: var(--glass-bg);
    color: var(--text-main);
    border: 1px solid var(--glass-border);
    font-weight: bold;
    font-size: 1.2rem;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
}
.btn-icon:hover {
    background: var(--btn-bg);
    color: var(--btn-text);
    transform: scale(1.1);
}

#langBtn {
    font-size: 0.9rem;
    font-weight: 800;
}

/* Guide Modal Overlay */
.guide-modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.7); /* dark overlay */
    z-index: 1000;
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
}
.guide-modal-overlay.show {
    opacity: 1;
    pointer-events: auto;
}

/* Guide Modal Content Box */
.guide-content {
    background: var(--bg-color); /* solid background */
    color: var(--text-main);
    border-radius: 24px;
    padding: 30px;
    width: 90%;
    max-width: 420px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    border: 2px solid var(--glass-border);
    transform: scale(0.8);
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    text-align: center;
}
.guide-modal-overlay.show .guide-content {
    transform: scale(1);
}

.guide-content h2 {
    color: var(--text-main);
    margin-bottom: 10px;
}
.guide-content ul {
    text-align: left;
    margin: 15px 0 25px 0;
    padding-left: 20px;
    color: var(--text-muted);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* Back Button */
.btn-back {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 5px;
    transition: all 0.3s;
    margin-bottom: 15px;
    padding: 0;
}
.btn-back:hover {
    color: var(--text-main);
    transform: translateX(-3px);
}

/* Round Splash Transition */
.round-splash {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    background: transparent;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.5s ease;
}

.round-splash h2 {
    font-size: 2.5rem;
    color: var(--text-main);
    transform: scale(0.5);
    transition: transform 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.round-splash.active {
    opacity: 1;
}
.round-splash.active h2 {
    transform: scale(1);
}

#gameUI {
    transition: opacity 0.5s ease;
}

/* Footer Link */
.footer-link {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.75rem;
    letter-spacing: 2px;
    font-weight: 600;
    transition: color 0.3s ease;
    z-index: 10;
}

.footer-link:hover {
    color: var(--text-main);
}