:root {
    --bg-1: #f7f4eb;
    --bg-2: #efe6d2;
    --card: rgba(255, 255, 255, 0.9);
    --card-solid: #ffffff;
    --text: #1f1d18;
    --muted: #696356;
    --line: rgba(31, 29, 24, 0.13);
    --teal: #0d766e;
    --teal-dark: #00ffee;
    --orange: #369e1a;
    --blue: #1f5f8b;
    --danger: #b42318;
    --radius-lg: 18px;
    --radius-sm: 10px;
    --shadow: 0 18px 40px rgba(31, 29, 24, 0.18);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: "Segoe UI", Tahoma, Verdana, sans-serif;
    color: var(--text);
    padding: 24px;
    background:
        radial-gradient(1200px 700px at 5% -20%, #f6c58c 0%, transparent 55%),
        radial-gradient(1000px 700px at 105% 0%, #9cc8d8 0%, transparent 60%),
        linear-gradient(170deg, var(--bg-1), var(--bg-2));
}

.layout {
    width: min(1180px, 100%);
    margin: 0 auto;
    display: grid;
    gap: 16px;
}

.banner {
    background: linear-gradient(135deg, var(--teal), var(--orange));
    color: #fff;
    border-radius: var(--radius-lg);
    padding: 18px 20px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}

.banner h1 {
    margin: 0;
    font-size: clamp(1.05rem, 2.5vw, 1.45rem);
    letter-spacing: 0.3px;
}

.pill {
    border: 1px solid rgba(255, 255, 255, 0.45);
    background: rgba(255, 255, 255, 0.2);
    padding: 7px 12px;
    border-radius: 999px;
    font-size: 0.82rem;
    font-weight: 700;
    white-space: nowrap;
}

.board {
    display: grid;
    grid-template-columns: 1.15fr 1fr;
    gap: 16px;
}

.card {
    background: var(--card);
    border: 1px solid rgba(255, 255, 255, 0.48);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    min-height: 620px;
    overflow: hidden;
}

.card-head {
    padding: 14px 16px;
    background: var(--card-solid);
    border-bottom: 1px solid var(--line);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.card-head h2 {
    margin: 0;
    font-size: 1rem;
}

.step {
    font-size: 0.8rem;
    font-weight: 700;
    color: var(--muted);
    border: 1px solid var(--line);
    border-radius: 999px;
    padding: 4px 10px;
    background: #fffdf8;
}

.teacher-tools {
    border-bottom: 1px solid var(--line);
    padding: 12px 14px;
    background: #fffef9;
    display: grid;
    gap: 8px;
}

.teacher-tools label {
    font-size: 0.82rem;
    color: var(--muted);
    font-weight: 700;
}

.row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 8px;
}

input,
textarea,
select,
button {
    font: inherit;
}

input,
textarea,
select {
    border: 1px solid rgba(31, 29, 24, 0.2);
    border-radius: var(--radius-sm);
    padding: 10px 12px;
    outline: none;
    background: #fff;
}

input:focus,
textarea:focus,
select:focus {
    border-color: var(--teal);
    box-shadow: 0 0 0 3px rgba(13, 118, 110, 0.15);
}

.btn {
    border: none;
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-weight: 700;
    color: #fff;
    cursor: pointer;
    background: linear-gradient(135deg, var(--blue), #114260);
    transition: filter 0.15s ease;
}

.btn:hover {
    filter: brightness(1.06);
}

.btn.secondary {
    background: linear-gradient(135deg, var(--teal), var(--teal-dark));
}

.btn.quiz {
    background: linear-gradient(135deg, var(--orange), #9f5113);
}

.chat-flow {
    padding: 12px 14px;
    border-bottom: 1px solid var(--line);
    color: var(--muted);
    font-size: 0.9rem;
    line-height: 1.45;
    background: #fff;
}

.messages {
    flex: 1;
    overflow-y: auto;
    min-height: 240px;
    max-height: 340px;
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    background: linear-gradient(180deg, #fffefc, #fff9ee);
}

.message {
    max-width: 78%;
    border-radius: 13px;
    padding: 10px 12px;
    line-height: 1.35;
    word-wrap: break-word;
}

.message.user {
    background: var(--teal);
    color: #fff;
    align-self: flex-end;
    border-bottom-right-radius: 2px;
}

.message.bot {
    background: #fff;
    border: 1px solid var(--line);
    color: #2d2a23;
    align-self: flex-start;
    border-bottom-left-radius: 2px;
}

.message.system {
    background: #f1f8ff;
    border: 1px solid #bfd6ea;
    color: #1b4f72;
    align-self: center;
}

.chat-input {
    padding: 12px;
    border-top: 1px solid var(--line);
    background: #fffdf7;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 8px;
}

.quiz-status {
    padding: 12px 14px;
    border-bottom: 1px solid var(--line);
    display: grid;
    gap: 8px;
    background: #fffdf8;
}

.quiz-stats {
    display: flex;
    justify-content: space-between;
    font-size: 0.9rem;
    color: var(--muted);
    font-weight: 700;
}

.progress-track {
    height: 14px;
    border-radius: 999px;
    background: #ebdfcb;
    overflow: hidden;
    border: 1px solid rgba(31, 29, 24, 0.1);
}

.progress-bar {
    height: 100%;
    width: 0;
    background: linear-gradient(90deg, var(--orange), var(--teal));
    transition: width 0.35s ease;
}

.quiz-gate {
    padding: 14px;
    border-bottom: 1px solid var(--line);
    background: #fff;
    display: grid;
    gap: 10px;
    color: var(--muted);
    font-size: 0.92rem;
}

.quiz-content {
    flex: 1;
    padding: 16px;
    display: grid;
    align-content: center;
    gap: 14px;
    background: linear-gradient(180deg, #fffefb, #fff8ec);
}

.question {
    margin: 0;
    text-align: center;
    line-height: 1.4;
    font-size: 1.12rem;
    font-weight: 700;
}

.options {
    display: grid;
    gap: 10px;
    grid-template-columns: 1fr 1fr;
}

.option-btn {
    border: 1px solid rgba(193, 107, 31, 0.4);
    background: #fff;
    color: #5d370f;
    border-radius: var(--radius-sm);
    padding: 11px;
    font-weight: 700;
    cursor: pointer;
    transition: background-color 0.12s ease, transform 0.12s ease;
}

.option-btn:hover:not(:disabled) {
    background: #fff2df;
    transform: translateY(-1px);
}

.option-btn:disabled,
.btn:disabled {
    cursor: not-allowed;
    opacity: 0.55;
}

.status {
    margin: 0;
    color: var(--muted);
    text-align: center;
}

.error {
    color: var(--danger);
    font-weight: 700;
}

.leaderboard-card {
    background: var(--card);
    border: 1px solid rgba(255, 255, 255, 0.48);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    backdrop-filter: blur(8px);
    overflow: hidden;
}

.leaderboard-tools {
    border-bottom: 1px solid var(--line);
    padding: 12px 14px;
    background: #fffef9;
    display: grid;
    gap: 8px;
}

.leaderboard-tools label {
    font-size: 0.82rem;
    color: var(--muted);
    font-weight: 700;
}

.leaderboard-list-wrap {
    padding: 14px;
    background: linear-gradient(180deg, #fffefc, #fff9ee);
}

.leaderboard-list {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 8px;
}

.leaderboard-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    padding: 9px 11px;
    background: #fff;
}

.leader-name {
    font-weight: 700;
    color: #2d2a23;
}

.leader-score {
    font-weight: 700;
    color: var(--blue);
}

@media (max-width: 1000px) {
    body {
        padding: 14px;
    }

    .banner {
        flex-direction: column;
        align-items: flex-start;
    }

    .board {
        grid-template-columns: 1fr;
    }

    .card {
        min-height: 560px;
    }

    .options {
        grid-template-columns: 1fr;
    }
}