/* ============================================
   DUO-STYLE.CSS - DUOLINGO STYLE REDESIGN
   Màu sắc & Typography đúng chuẩn Duolingo
   ============================================ */

/* Import font */
@import url('https://fonts.googleapis.com/css2?family=Nunito:wght@400;600;700;800;900&display=swap');

/* ---- Root Variables ---- */
:root {
    --duo-green:       #58cc02;
    --duo-green-dark:  #46a302;
    --duo-blue:        #1cb0f6;
    --duo-blue-dark:   #0094d8;
    --duo-red:         #ff4b4b;
    --duo-orange:      #ff9600;
    --duo-yellow:      #ffc800;
    --duo-purple:      #ce82ff;
    --duo-bg:          #f7f7f7;
    --duo-white:       #ffffff;
    --duo-border:      #e5e5e5;
    --duo-text-dark:   #3c3c3c;
    --duo-text-mid:    #6b6b6b;
    --duo-text-light:  #afafaf;
    --duo-shadow:      rgba(0,0,0,0.08);
    --duo-radius:      16px;
    --duo-radius-lg:   24px;
    --duo-radius-pill: 100px;
    --duo-font:        'Nunito', 'Inter', sans-serif;
}

/* ---- Wrapper ---- */
.duo-wrapper {
    font-family: var(--duo-font);
    background: var(--duo-bg);
    min-height: 100vh;
    padding: 0;
    color: var(--duo-text-dark);
}

.duo-container {
    max-width: 480px;
    margin: 0 auto;
    padding: 1.5rem 1rem 3rem;
    background: var(--duo-bg);
    color: var(--duo-text-dark);
    font-family: var(--duo-font);
}

/* ---- Auth Box ---- */
.duo-auth-box {
    background: var(--duo-white);
    border-radius: var(--duo-radius-lg);
    box-shadow: 0 4px 0 var(--duo-border);
    padding: 2rem 1.5rem;
    margin-bottom: 1.5rem;
    text-align: center;
}

.duo-auth-title {
    font-size: 1.4rem;
    font-weight: 800;
    margin-bottom: 1.2rem;
    color: var(--duo-text-dark);
}

.duo-text-input {
    width: 100%;
    padding: 14px 16px;
    font-size: 1rem;
    font-family: var(--duo-font);
    font-weight: 600;
    border: 2px solid var(--duo-border);
    border-radius: var(--duo-radius);
    background: var(--duo-white);
    color: var(--duo-text-dark);
    outline: none;
    box-sizing: border-box;
    transition: border-color 0.2s;
    margin-bottom: 10px;
    display: block;
}

.duo-text-input:focus {
    border-color: var(--duo-blue);
}

.duo-auth-status {
    font-size: 0.85rem;
    font-weight: 700;
    padding: 6px 14px;
    border-radius: var(--duo-radius-pill);
    display: inline-block;
    margin-bottom: 1rem;
}

/* ---- STAT CARDS (Dashboard) ---- */
.duo-stats-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 1.2rem;
}

.duo-stat-card {
    background: var(--duo-white);
    border-radius: var(--duo-radius);
    box-shadow: 0 3px 0 var(--duo-border);
    padding: 1rem 0.5rem;
    text-align: center;
}

.duo-stat-icon { font-size: 1.6rem; line-height: 1; margin-bottom: 4px; }
.duo-stat-value { font-size: 1.7rem; font-weight: 900; color: var(--duo-text-dark); line-height: 1.1; }
.duo-stat-label { font-size: 0.65rem; text-transform: uppercase; font-weight: 700; color: var(--duo-text-light); margin-top: 3px; letter-spacing: 0.5px; }

/* ---- Status badge ---- */
.duo-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 18px;
    border-radius: var(--duo-radius-pill);
    font-size: 0.85rem;
    font-weight: 700;
    margin-bottom: 1.2rem;
}

.duo-badge-done   { background: #d7ffb8; color: var(--duo-green-dark); }
.duo-badge-undone { background: #fff3cd; color: #b07800; }

/* ---- Rule Box ---- */
.duo-rule-box {
    background: var(--duo-white);
    border-radius: var(--duo-radius);
    box-shadow: 0 3px 0 var(--duo-border);
    padding: 1.2rem 1.4rem;
    margin-bottom: 1.5rem;
    text-align: left;
}

.duo-rule-box h3 {
    font-size: 0.9rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--duo-text-light);
    margin-bottom: 0.8rem;
}

.duo-rule-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.duo-rule-list li {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--duo-text-mid);
    padding: 5px 0;
    border-bottom: 1px solid var(--duo-border);
}

.duo-rule-list li:last-child { border-bottom: none; }
.duo-rule-list li .rule-icon { font-size: 1.1rem; flex-shrink: 0; margin-top: 1px; }

/* ---- PATH LAYOUT ---- */
.duo-path-container {
    display: flex;
    flex-direction: column-reverse; /* Bottom to top */
    align-items: center;
    padding: 20px 0 40px;
    position: relative;
    gap: 40px;
}

.duo-path-node-wrapper {
    position: relative;
    width: 100%;
    display: flex;
    justify-content: center;
}

/* Winding logic using nth-child */
.duo-path-node-wrapper:nth-child(4n+1) { transform: translateX(0px); }
.duo-path-node-wrapper:nth-child(4n+2) { transform: translateX(-40px); }
.duo-path-node-wrapper:nth-child(4n+3) { transform: translateX(0px); }
.duo-path-node-wrapper:nth-child(4n+4) { transform: translateX(40px); }

.duo-path-node {
    width: 70px;
    height: 70px;
    border-radius: 50%;
    background: var(--duo-border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8rem;
    color: white;
    font-weight: 900;
    position: relative;
    z-index: 2;
    box-shadow: 0 6px 0 #d0d0d0;
    cursor: pointer;
    transition: 0.1s;
}

.duo-path-node:active {
    transform: translateY(6px);
    box-shadow: 0 0px 0 transparent;
}

/* Nút đã qua */
.duo-path-node.completed {
    background: var(--duo-yellow);
    box-shadow: 0 6px 0 #d07a00;
}

/* Nút hiện tại */
.duo-path-node.current {
    background: var(--duo-green);
    box-shadow: 0 6px 0 var(--duo-green-dark);
    animation: bounce 2s infinite;
}

/* Nút bị khóa */
.duo-path-node.locked {
    background: #e5e5e5;
    box-shadow: 0 6px 0 #cecece;
    color: #afafaf;
    cursor: default;
}
.duo-path-node.locked:active {
    transform: none;
    box-shadow: 0 6px 0 #cecece;
}

/* Nút Start bay lơ lửng */
.duo-start-tooltip {
    position: absolute;
    top: -50px;
    background: var(--duo-white);
    color: var(--duo-green);
    border: 2px solid var(--duo-border);
    padding: 8px 16px;
    border-radius: var(--duo-radius-pill);
    font-weight: 800;
    font-size: 0.9rem;
    letter-spacing: 1px;
    box-shadow: 0 4px 10px var(--duo-shadow);
    white-space: nowrap;
    animation: float 2s infinite ease-in-out;
}
.duo-start-tooltip::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    border-width: 8px 8px 0;
    border-style: solid;
    border-color: var(--duo-white) transparent transparent transparent;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {transform: translateY(0);}
    40% {transform: translateY(-15px);}
    60% {transform: translateY(-7px);}
}

/* ---- BUTTONS ---- */
.duo-btn {
    display: block;
    width: 100%;
    padding: 16px;
    font-size: 1rem;
    font-family: var(--duo-font);
    font-weight: 800;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: white;
    background: var(--duo-green);
    border: none;
    border-bottom: 4px solid var(--duo-green-dark);
    border-radius: var(--duo-radius-pill);
    cursor: pointer;
    transition: transform 0.1s, filter 0.1s;
    margin-bottom: 10px;
    box-sizing: border-box;
}

.duo-btn:active { transform: translateY(3px); border-bottom-width: 1px; }
.duo-btn:hover:not(:disabled) { filter: brightness(1.07); }
.duo-btn:disabled { background: #e5e5e5; border-bottom-color: #d0d0d0; color: #afafaf; cursor: default; }

.duo-btn-blue   { background: var(--duo-blue);   border-bottom-color: var(--duo-blue-dark); }
.duo-btn-red    { background: var(--duo-red);    border-bottom-color: #cc0000; }
.duo-btn-orange { background: var(--duo-orange); border-bottom-color: #d07a00; }

.duo-btn-ghost {
    background: var(--duo-white);
    color: var(--duo-blue);
    border: 2px solid var(--duo-border);
    border-bottom: 4px solid var(--duo-border);
}
.duo-btn-ghost:hover:not(:disabled) { background: #f0f9ff; border-color: var(--duo-blue); color: var(--duo-blue-dark); filter: none; }

/* ---- GAME SCREEN ---- */

/* Header bar (level + hearts) */
.duo-game-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 1.2rem;
}

.duo-level-pill {
    background: var(--duo-blue);
    color: white;
    font-weight: 900;
    font-size: 0.85rem;
    padding: 6px 16px;
    border-radius: var(--duo-radius-pill);
    letter-spacing: 0.5px;
    flex-shrink: 0;
    white-space: nowrap;
}

/* Progress bar */
.duo-progress-bar {
    flex: 1;
    height: 16px;
    background: var(--duo-border);
    border-radius: var(--duo-radius-pill);
    overflow: hidden;
}

.duo-progress-fill {
    height: 100%;
    background: var(--duo-green);
    border-radius: var(--duo-radius-pill);
    transition: width 0.3s ease;
}

.duo-hearts-display {
    font-size: 1.3rem;
    flex-shrink: 0;
    letter-spacing: 2px;
}

/* Game Card */
.duo-game-card {
    background: var(--duo-white);
    border-radius: var(--duo-radius-lg);
    box-shadow: 0 4px 0 var(--duo-border);
    padding: 1.5rem;
    margin-bottom: 1.2rem;
    text-align: center;
}

.duo-game-instruction {
    font-size: 0.85rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--duo-text-light);
    margin-bottom: 1rem;
}

/* The big number */
.duo-big-number {
    font-family: var(--duo-font);
    font-size: clamp(2.5rem, 8vw, 4.5rem);
    font-weight: 900;
    color: var(--duo-text-dark);
    letter-spacing: 8px;
    line-height: 1.1;
    word-break: break-all;
    margin-bottom: 1rem;
    min-height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Countdown ring / timer */
.duo-timer-bar {
    width: 100%;
    height: 8px;
    background: var(--duo-border);
    border-radius: var(--duo-radius-pill);
    overflow: hidden;
    margin-top: 0.5rem;
}
.duo-timer-fill {
    height: 100%;
    background: var(--duo-orange);
    border-radius: var(--duo-radius-pill);
    transition: width 0.1s linear;
}

/* Answer input */
.duo-answer-input {
    width: 100%;
    padding: 16px;
    font-size: 1.8rem;
    font-family: var(--duo-font);
    font-weight: 900;
    text-align: center;
    letter-spacing: 6px;
    border: 3px solid var(--duo-border);
    border-radius: var(--duo-radius);
    background: var(--duo-white);
    color: var(--duo-text-dark);
    outline: none;
    box-sizing: border-box;
    transition: border-color 0.2s;
    margin-bottom: 1rem;
}
.duo-answer-input:focus { border-color: var(--duo-blue); }
.duo-answer-input.correct { border-color: var(--duo-green); background: #f0fff0; }
.duo-answer-input.wrong   { border-color: var(--duo-red);  background: #fff0f0; animation: duo-shake 0.4s; }

/* Result feedback panels */
.duo-feedback {
    border-radius: var(--duo-radius);
    padding: 1.2rem 1.5rem;
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    text-align: left;
}
.duo-feedback-correct { background: #d7ffb8; }
.duo-feedback-wrong   { background: #ffdfe0; }

.duo-feedback-icon { font-size: 1.6rem; flex-shrink: 0; }

.duo-feedback-title {
    font-weight: 900;
    font-size: 1rem;
    margin-bottom: 3px;
}
.duo-feedback-correct .duo-feedback-title { color: var(--duo-green-dark); }
.duo-feedback-wrong   .duo-feedback-title { color: var(--duo-red); }

.duo-feedback-sub { font-size: 0.85rem; font-weight: 600; color: var(--duo-text-mid); }

/* Level Up / Gameover screens */
.duo-result-screen {
    text-align: center;
    padding: 2rem 1rem;
}
.duo-result-emoji { font-size: 4rem; margin-bottom: 0.8rem; line-height: 1; }
.duo-result-title { font-size: 1.8rem; font-weight: 900; margin-bottom: 0.5rem; }
.duo-result-sub   { font-size: 0.95rem; font-weight: 600; color: var(--duo-text-mid); margin-bottom: 1.5rem; }

/* Separator */
.duo-divider { height: 1px; background: var(--duo-border); margin: 1rem 0; }

/* ---- Animations ---- */
@keyframes duo-shake {
    0%, 100% { transform: translateX(0); }
    20%       { transform: translateX(-8px); }
    60%       { transform: translateX(8px); }
}

@keyframes duo-pop {
    0%   { transform: scale(0.8); opacity: 0; }
    70%  { transform: scale(1.05); }
    100% { transform: scale(1); opacity: 1; }
}

.duo-pop { animation: duo-pop 0.35s ease; }

/* ---- Responsive ---- */
@media (max-width: 520px) {
    .duo-container { padding: 1rem 0.8rem 2rem; }
    .duo-game-card  { padding: 1rem; }
    .duo-stats-row  { gap: 8px; }
    .duo-stat-value { font-size: 1.4rem; }
    .duo-big-number { font-size: 2.2rem; letter-spacing: 5px; }
    .duo-answer-input { font-size: 1.4rem; letter-spacing: 4px; }
}