/* BIẾN MÀU SẮC CHỦ ĐẠO */
:root {
    /* Tông 1: Kẹo Ngọt (Mặc định) */
    --bg-main: #FDFBFB;
    --card-front-bg: #FFFFFF;
    --card-front-text: #5C4D7D;
    --card-front-border: #FFD1DC;
    --card-front-shadow: rgba(255, 182, 193, 0.15);
    --card-back-border: rgba(255, 255, 255, 0.6);
    --card-back-shadow: rgba(255, 158, 174, 0.2);
    --card-matched-text: #2B8A3E;

    --nav-bg-start: #FFF0F5;
    --nav-bg-end: #FFE4E1;
    --nav-border: #FFD1DC;
    --nav-shadow: rgba(255, 182, 193, 0.4);
    --game-title-color: #D81B60;

    --stat-match-bg: #E8F5E9;
    --stat-match-text: #2E7D32;
    --stat-match-border: #A5D6A7;
    --stat-move-bg: #FFF8E1;
    --stat-move-text: #F57F17;
    --stat-move-border: #FFE082;

    --timer-countdown-bg: #FF758C;
    --timer-warning-bg: #FFD54F;
    --timer-stopwatch-bg: #E1F5FE;
    --timer-stopwatch-text: #0288D1;
    --timer-none-bg: #F3E5F5;
    --timer-none-text: #7B1FA2;

    --btn-primary-start: #FF9EAE;
    --btn-primary-end: #FF758C;
    --modal-bg: #FFF0F5;
}

/* Tông 2: Đại Dương (Xanh Dương) */
[data-theme="blue"] {
    --bg-main: #F0F9FF;
    --card-front-text: #1E3A8A;
    --card-front-border: #BAE6FD;
    --card-front-shadow: rgba(186, 230, 253, 0.3);
    --card-matched-text: #059669;
    --nav-bg-start: #E0F2FE;
    --nav-bg-end: #F0FDFA;
    --nav-border: #7DD3FC;
    --nav-shadow: rgba(125, 211, 252, 0.3);
    --game-title-color: #0369A1;
    --btn-primary-start: #38BDF8;
    --btn-primary-end: #0EA5E9;
    --modal-bg: #F0F9FF;
}

/* Tông 3: Rừng Xanh (Xanh Lá) */
[data-theme="green"] {
    --bg-main: #F0FDF4;
    --card-front-text: #064E3B;
    --card-front-border: #BBF7D0;
    --card-front-shadow: rgba(187, 247, 208, 0.3);
    --card-matched-text: #15803D;
    --nav-bg-start: #DCFCE7;
    --nav-bg-end: #F0FDF4;
    --nav-border: #86EFAC;
    --nav-shadow: rgba(134, 239, 172, 0.3);
    --game-title-color: #166534;
    --btn-primary-start: #4ADE80;
    --btn-primary-end: #16A34A;
    --modal-bg: #F0FDF4;
}

/* Tông 4: Hoàng Hôn (Cam Đào) */
[data-theme="orange"] {
    --bg-main: #FFF7ED;
    --card-front-text: #7C2D12;
    --card-front-border: #FFEDD5;
    --card-front-shadow: rgba(255, 237, 213, 0.4);
    --card-matched-text: #C2410C;
    --nav-bg-start: #FFEDD5;
    --nav-bg-end: #FFF7ED;
    --nav-border: #FDBA74;
    --nav-shadow: rgba(253, 186, 116, 0.3);
    --game-title-color: #9A3412;
    --btn-primary-start: #FB923C;
    --btn-primary-end: #EA580C;
    --modal-bg: #FFF7ED;
}

/* Tông 5: Bóng Đêm (Dark Mode) */
[data-theme="dark"] {
    --bg-main: #0F172A;
    --card-front-bg: #1E293B;
    --card-front-text: #F1F5F9;
    --card-front-border: #334155;
    --card-front-shadow: rgba(0, 0, 0, 0.3);
    --card-back-border: rgba(255, 255, 255, 0.1);
    --card-back-shadow: rgba(0, 0, 0, 0.5);
    --card-matched-text: #4ADE80;
    --nav-bg-start: #1E293B;
    --nav-bg-end: #0F172A;
    --nav-border: #334155;
    --nav-shadow: rgba(0, 0, 0, 0.4);
    --game-title-color: #38BDF8;
    --btn-primary-start: #334155;
    --btn-primary-end: #475569;
    --modal-bg: #1E293B;
}

/* CSS GIAO DIỆN CHÍNH */
body { font-family: 'Quicksand', sans-serif !important; height: 100vh; display: flex; flex-direction: column; margin: 0; overflow: hidden; background-color: var(--bg-main); transition: background-color 0.3s; }
#game-container { flex-grow: 1; padding: 12px; display: flex; justify-content: center; align-items: center; min-height: 0; }
#game-board { display: grid; gap: 10px; width: 100%; height: 100%; }
#gameScreen {
    display: flex;
    flex-direction: column;
    height: 100%;
}
.memory-card { width: 100%; height: 100%; cursor: pointer; perspective: 1000px; transition: transform 0.2s ease; }
.memory-card:not(.flipped):hover { transform: translateY(-4px); }
.memory-card-inner { position: relative; width: 100%; height: 100%; text-align: center; transition: transform 0.6s cubic-bezier(0.4, 0.2, 0.2, 1); transform-style: preserve-3d; }
.memory-card.flipped .memory-card-inner { transform: rotateY(180deg); }
.memory-card.flipped .memory-card-back span, .memory-card.flipped .memory-card-back i { opacity: 0 }

.memory-card-front, .memory-card-back { position: absolute; width: 100%; height: 100%; backface-visibility: hidden; display: flex; align-items: center; justify-content: center; border-radius: 0.8rem; padding: 5px; font-size: clamp(15px, 3.5vmin, 30px); transition: background-color 0.4s, border-color 0.4s, box-shadow 0.4s; }

.memory-card-front { background-color: var(--card-front-bg); color: var(--card-front-text); border: 2px solid var(--card-front-border); font-weight: 700; transform: rotateY(180deg); box-shadow: 0 4px 6px var(--card-front-shadow); }
.memory-card-back { color: #FFFFFF; font-size: clamp(40px, 10vmin, 60px); font-weight: 800; border: 2px solid var(--card-back-border); box-shadow: 0 4px 0 var(--card-back-shadow); text-shadow: 0px 2px 5px rgba(0, 0, 0, 0.15); }
.memory-card.matched .memory-card-front { color: var(--card-matched-text); }

/* NAVBAR KẸO NGỌT */
.candy-navbar { flex-shrink: 0; z-index: 10; background: linear-gradient(135deg, var(--nav-bg-start) 0%, var(--nav-bg-end) 100%) !important; border-bottom: 3px dashed var(--nav-border); box-shadow: 0 4px 15px var(--nav-shadow) !important; }
.game-title { font-weight: 900; color: var(--game-title-color) !important; text-shadow: 2px 2px 0px rgba(255, 255, 255, 0.9); }
.stat-badge { font-weight: 800; border-width: 2px; border-style: solid; }

.candy-badge-match { background-color: var(--stat-match-bg); color: var(--stat-match-text); border-color: var(--stat-match-border); }
.candy-badge-move { background-color: var(--stat-move-bg); color: var(--stat-move-text); border-color: var(--stat-move-border); }

.candy-timer-countdown { background-color: var(--timer-countdown-bg); color: white; border-color: var(--timer-countdown-bg); }
.candy-timer-warning { background-color: var(--timer-warning-bg); color: var(--game-title-color); border-color: var(--timer-warning-bg); animation: heartBeat 0.8s infinite alternate; }
.candy-timer-stopwatch { background-color: var(--timer-stopwatch-bg); color: var(--timer-stopwatch-text); border-color: #81D4FA; }
.candy-timer-none { background-color: var(--timer-none-bg); color: var(--timer-none-text); border-color: #CE93D8; }

@keyframes heartBeat { 0% { transform: scale(1); } 100% { transform: scale(1.08); } }

.btn-settings { background-color: #FFFFFF; border: 2px solid var(--nav-border); color: var(--game-title-color) !important; }
#restart-btn { background: linear-gradient(135deg, var(--btn-primary-start) 0%, var(--btn-primary-end) 100%); border: none; color: white; }

/* MODAL KẸO NGỌT */
.candy-modal { background-color: var(--modal-bg); border-radius: 1.5rem !important; border: 4px solid var(--nav-border); overflow: hidden; }
.candy-modal .modal-header { background: linear-gradient(135deg, var(--btn-primary-start) 0%, var(--btn-primary-end) 100%); border-bottom: 2px dashed #FFF; }
.candy-modal .modal-title { color: #FFFFFF !important; font-weight: 900; }
.candy-modal .form-label { color: var(--game-title-color); font-weight: 800; }
.candy-modal .form-select, .candy-modal .form-control { border: 2px solid var(--nav-border); border-radius: 1rem; font-weight: 700; }
.candy-btn-save { background: linear-gradient(135deg, var(--btn-primary-start) 0%, var(--btn-primary-end) 100%); border: none; color: white; font-weight: 700; }
.btn-reset-settings { color: #6c757d !important; font-weight: 600; text-decoration: none; font-size: 0.9rem; transition: color 0.2s; }
.btn-reset-settings:hover { color: #dc3545 !important; }

#resultIcon { font-size: 5rem; display: block; margin-bottom: 1rem; }
.result-text { font-weight: 800; color: var(--game-title-color); }

/* WELCOME & HELP SCREENS */
#welcomeScreen, #helpScreen {
    font-family: 'Quicksand', sans-serif !important;
    background-color: #090a0f;
    color: #ffffff;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    z-index: 99999;
}
#helpScreen {
    z-index: 99998;
}

#welcomeScreen.fade-out, #helpScreen.fade-out {
    pointer-events: none;
    opacity: 0;
    transform: scale(1.1);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

/* Stars Background */
#welcomeScreen .stars, #helpScreen .stars {
    position: absolute;
    top: 0;
    left: 0;
    width: 200%;
    height: 200%;
    background-image:
        radial-gradient(2px 2px at 20px 30px, #ffffff, rgba(0,0,0,0)),
        radial-gradient(2px 2px at 40px 70px, #ffffff, rgba(0,0,0,0)),
        radial-gradient(2px 2px at 50px 160px, #ffffff, rgba(0,0,0,0)),
        radial-gradient(2px 2px at 90px 40px, #ffffff, rgba(0,0,0,0)),
        radial-gradient(2px 2px at 130px 80px, #ffffff, rgba(0,0,0,0)),
        radial-gradient(2px 2px at 160px 120px, #ffffff, rgba(0,0,0,0));
    background-repeat: repeat;
    background-size: 200px 200px;
    animation: moveStars 150s linear infinite;
    z-index: 0;
}
#welcomeScreen .stars1, #helpScreen .stars1 { animation-duration: 50s; opacity: 0.3; }
#welcomeScreen .stars2, #helpScreen .stars2 { animation-duration: 100s; opacity: 0.2; transform: scale(1.5); }
#welcomeScreen .stars3, #helpScreen .stars3 { animation-duration: 150s; opacity: 0.1; transform: scale(2); }

@keyframes moveStars {
    0% { transform: translateY(0); }
    100% { transform: translateY(-200px); }
}

#welcomeScreen::after, #helpScreen::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: radial-gradient(circle at center, rgba(66, 153, 225, 0.15) 0%, rgba(0, 0, 0, 0) 60%);
    z-index: 0;
    pointer-events: none;
}

/* Header */
.ws-header {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 10;
}

.ws-logo-container {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: 15px;
    margin-left: 15px;
}
.ws-logo-container::before {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    width: 150px;
    height: 150px;
    background: radial-gradient(circle, rgba(66, 153, 225, 0.4) 0%, rgba(159, 122, 234, 0.2) 40%, rgba(0, 0, 0, 0) 70%);
    border-radius: 50%;
    z-index: -1;
    filter: blur(15px);
    animation: pulseNebula 4s ease-in-out infinite alternate;
}
@keyframes pulseNebula {
    0% { transform: translate(-50%, -50%) scale(0.8); opacity: 0.5; }
    100% { transform: translate(-50%, -50%) scale(1.1); opacity: 1; }
}

.ws-logo {
    max-width: 120px;
    height: auto;
    filter: drop-shadow(0 0 10px rgba(255, 255, 255, 0.5));
    animation: floatLogo 6s ease-in-out infinite;
}
@keyframes floatLogo {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

/* Main */
.ws-main {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 1rem;
    position: relative;
    z-index: 1;
}

.ws-content-wrapper {
    text-align: center;
    padding: 2rem;
    width: 100%;
    max-width: 800px;
    animation: fadeInScale 1s ease-out forwards;
}
@keyframes fadeInScale {
    from { opacity: 0; transform: scale(0.9); }
    to { opacity: 1; transform: scale(1); }
}

.ws-game-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    line-height: 1.2;
    color: #fff;
    margin: 0;
    background: linear-gradient(to right, #4fd1c5, #f687b3, #4fd1c5);
    background-size: 200% auto;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: gradientText 5s linear infinite;
    filter: drop-shadow(0 0 10px rgba(246, 135, 179, 0.5));
    font-weight: 800;
}
@keyframes gradientText {
    0% { background-position: 0% center; }
    100% { background-position: 200% center; }
}

.ws-game-subtitle {
    font-size: clamp(1rem, 3vw, 1.25rem);
    color: #e2e8f0;
    font-weight: 600;
    margin-top: 1rem;
    margin-bottom: 0;
    opacity: 0;
    letter-spacing: 0.5px;
    animation: fadeIn 2s ease-out 0.5s forwards;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 0.9; transform: translateY(0); }
}

.ws-button-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    margin-top: 3rem;
}

/* Cosmic Button Styling */
.ws-btn-primary-cosmic {
    position: relative;
    padding: 1rem 3.5rem;
    font-size: 1.5rem;
    font-family: 'Quicksand', sans-serif;
    font-weight: 700;
    color: #fff;
    background: #0f172a;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    overflow: hidden;
    z-index: 1;
    transition: transform 0.2s, box-shadow 0.2s;
    margin-bottom: 0.5rem;
    text-decoration: none;
    display: inline-block;
}
.ws-btn-primary-cosmic::before {
    content: '';
    position: absolute;
    top: -3px; left: -3px; right: -3px; bottom: -3px;
    z-index: -1;
    background: linear-gradient(45deg, #4299e1, #9f7aea, #ed64a6, #4299e1);
    background-size: 400%;
    border-radius: 52px;
    animation: animateBorder 4s linear infinite;
    opacity: 0.8;
    transition: opacity 0.3s;
}
.ws-btn-primary-cosmic::after {
    content: '';
    position: absolute;
    top: 3px; left: 3px; right: 3px; bottom: 3px;
    background: #0f172a;
    border-radius: 48px;
    z-index: -1;
    transition: background 0.3s;
}
.ws-btn-primary-cosmic:hover::after {
    background: #1e3a8a;
}
.ws-btn-primary-cosmic span {
    position: relative;
    z-index: 2;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
    display: inline-block;
    transition: transform 0.2s;
}
.ws-btn-primary-cosmic:hover span {
    transform: scale(1.05);
}
.ws-btn-primary-cosmic:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.5);
}
.ws-btn-primary-cosmic:hover::before {
    opacity: 1;
}
.ws-btn-primary-cosmic:active {
    transform: translateY(1px);
}
@keyframes animateBorder {
    0% { background-position: 0 0; }
    50% { background-position: 300% 0; }
    100% { background-position: 0 0; }
}

.ws-more-games-link {
    color: #a0aec0;
    font-size: 1.1rem;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    display: inline-block;
}
.ws-more-games-link:hover {
    color: #fff;
    background-color: rgba(255, 255, 255, 0.1);
    text-shadow: 0 0 8px rgba(255, 255, 255, 0.5);
    transform: translateY(-1px);
}

.ws-credit {
    position: absolute;
    bottom: 1rem;
    left: 0;
    width: 100%;
    text-align: center;
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.4);
    letter-spacing: 1px;
    z-index: 10;
}
.ws-credit a {
    color: #9f7aea;
    font-weight: 700;
    text-decoration: none;
    transition: color 0.3s, text-shadow 0.3s;
}
.ws-credit a:hover {
    color: #fff;
    text-shadow: 0 0 8px rgba(159, 122, 234, 0.8);
}

/* Help Screen Boxes */
.instruction-box, .question-count {
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0.08));
    transition: 0.3s;
}
.check-icon {
    font-size: 1.4rem;
    color: #a7f3d0;
}
.question-count {
    font-size: 1.25rem;
    color: #63b3ed;
}

/* Help Screen Buttons */
.btn-fullscreen, .btn-play {
    position: relative;
    z-index: 1;
    margin-bottom: 0.5rem;
    padding: 1rem 2rem;
    overflow: hidden;
    font-family: 'Quicksand', sans-serif;
    font-weight: 700;
    color: #fff;
    cursor: pointer;
    background: #0f172a;
    border: none;
    border-radius: 8px;
    transition: transform 0.2s, box-shadow 0.2s;
}
.btn-fullscreen span, .btn-play span {
    position: relative;
    z-index: 2;
    display: inline-block;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    transition: transform 0.2s;
}
.btn-fullscreen::before, .btn-play::before {
    content: '';
    position: absolute;
    top: -3px; right: -3px; bottom: -3px; left: -3px;
    z-index: -1;
    background: linear-gradient(45deg, #4299e1, #9f7aea, #ed64a6, #4299e1);
    background-size: 400%;
    border-radius: 8px;
    opacity: 0.8;
    animation: animateBorder 4s linear infinite;
    transition: opacity 0.3s;
}
.btn-fullscreen::after, .btn-play::after {
    content: '';
    position: absolute;
    top: 2px; right: 2px; bottom: 2px; left: 2px;
    z-index: -1;
    background: #0f172a;
    border-radius: 6px;
    transition: background 0.3s;
}
.btn-fullscreen:hover::after, .btn-play:hover::after {
    background: #1e3a8a;
}
.btn-fullscreen:hover::before, .btn-play:hover::before {
    opacity: 1;
}
.btn-fullscreen:hover span, .btn-play:hover span {
    transform: scale(1.05);
}
.btn-fullscreen:hover, .btn-play:hover {
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.5);
}
.btn-fullscreen::before {
    animation: none;
}