:root {
    --bg-color: #F5F5F7;
    --panel-bg: rgba(255, 255, 255, 0.85);
    --panel-border: rgba(0, 0, 0, 0.08);
    --text-primary: #1D1D1F;
    --text-secondary: #86868B;
    --system-blue: #007AFF;
    --system-blue-hover: #0056B3;
    --system-green: #34C759;
    --system-green-hover: #2BAA49;
    --system-red: #FF3B30;
    --system-red-hover: #D70015;
    
    --radius-lg: 18px;
    --radius-md: 12px;
    --radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
    --shadow-soft: 0 4px 24px rgba(0, 0, 0, 0.04);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "Helvetica Neue", Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
}

body {
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at 50% 0%, #FFFFFF 0%, #F5F5F7 80%);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
}

.screen {
    display: none;
    width: 100%;
    height: 100%;
}
.screen.active {
    display: flex;
    flex-direction: column;
}

/* Glassmorphism Panels */
.glass-panel {
    background: var(--panel-bg);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--panel-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-soft);
}

/* --- Login Screen --- */
#login-screen {
    justify-content: center;
    align-items: center;
}
.login-card {
    padding: 48px 40px;
    width: 400px;
    text-align: center;
}
.login-card h1 {
    margin-bottom: 32px;
    font-weight: 600;
    font-size: 28px;
    letter-spacing: -0.5px;
}
input, textarea {
    width: 100%;
    padding: 14px 16px;
    margin-bottom: 16px;
    background: #FFFFFF;
    border: 1px solid var(--panel-border);
    color: var(--text-primary);
    border-radius: var(--radius-md);
    font-size: 16px;
    outline: none;
    transition: var(--transition);
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.02);
}
input::placeholder, textarea::placeholder {
    color: var(--text-secondary);
}
input:focus, textarea:focus {
    border-color: var(--system-blue);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.2);
}
.error-msg {
    color: var(--system-red);
    margin-top: 12px;
    font-size: 14px;
    height: 20px;
    font-weight: 500;
}

/* --- Buttons --- */
button {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    color: white;
}
button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    transform: none !important;
}
button:active:not(:disabled) {
    transform: scale(0.97);
}
.btn-primary { background: var(--system-blue); }
.btn-primary:hover:not(:disabled) { background: var(--system-blue-hover); }
.btn-success { background: var(--system-green); }
.btn-success:hover:not(:disabled) { background: var(--system-green-hover); }
.btn-danger { background: var(--system-red); }
.btn-danger:hover:not(:disabled) { background: var(--system-red-hover); }
.btn-inline { width: auto; padding: 10px 18px; font-size: 14px; }

/* --- Dashboard --- */
header {
    margin: 20px 24px;
    padding: 18px 28px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.header-left { display: flex; align-items: center; gap: 20px; }
.header-left h2 { font-weight: 600; font-size: 20px; letter-spacing: -0.3px; }
.status-badge {
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.connected { background: rgba(52, 199, 89, 0.15); color: var(--system-green); }
.disconnected { background: rgba(255, 59, 48, 0.15); color: var(--system-red); }
.state-badge {
    background: rgba(0, 0, 0, 0.04);
    color: var(--text-secondary);
    padding: 8px 16px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 13px;
    letter-spacing: 0.5px;
    border: 1px solid rgba(0,0,0,0.02);
}

.main-layout {
    display: flex;
    flex: 1;
    gap: 24px;
    padding: 0 24px 24px 24px;
    overflow: hidden;
}

/* Tabs inside main layout */
.tabs-container {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;
    background: var(--panel-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--panel-border);
    box-shadow: var(--shadow-soft);
    overflow: hidden;
}

.tabs-header {
    display: flex;
    gap: 12px;
    padding: 20px 24px;
    border-bottom: 1px solid var(--panel-border);
    background: rgba(255, 255, 255, 0.4);
    flex-wrap: wrap;
}

.tab-btn {
    padding: 10px 20px;
    cursor: pointer;
    background: transparent;
    border: none;
    border-radius: 100px;
    font-weight: 600;
    font-size: 15px;
    color: var(--text-secondary);
    transition: var(--transition);
    width: auto;
}
.tab-btn:hover {
    background: rgba(0, 0, 0, 0.03);
    color: var(--text-primary);
}
.tab-btn.active {
    background: #FFFFFF;
    color: var(--system-blue);
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.tab-content {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
}
.tab-pane { display: none; }
.tab-pane.active { display: block; animation: fadeIn 0.3s ease; }

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(4px); }
    to { opacity: 1; transform: translateY(0); }
}

/* General Layout Elements */
.section-block {
    margin-bottom: 32px;
    padding: 24px;
    background: #FFFFFF;
    border: 1px solid var(--panel-border);
    border-radius: var(--radius-lg);
    box-shadow: 0 2px 12px rgba(0,0,0,0.02);
}
.section-block h3 { margin-bottom: 16px; font-size: 18px; font-weight: 600; color: var(--text-primary); }

.form-grid { display: grid; gap: 16px; grid-template-columns: repeat(3, minmax(0, 1fr)); margin-bottom: 20px; }
.form-grid.two-col { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.full-span { grid-column: 1 / -1; }
.action-row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 16px; }
.toolbar-row { display: flex; gap: 16px; align-items: end; margin-bottom: 20px; flex-wrap: wrap; }
.toolbar-item { min-width: 240px; flex: 1; }
.toolbar-item label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.5px;}

.muted-text { color: var(--text-secondary); font-size: 13px; line-height: 1.5; }
.empty-hint { margin: 12px 0; color: var(--text-secondary); font-size: 14px; }
.danger-note { color: var(--system-red); font-size: 13px; margin-top: 8px; }
.hidden { display: none !important; }

/* Control Panel */
.dashboard-grid {
    display: flex;
    gap: 24px;
    height: 100%;
}
.control-panel {
    width: 320px;
    padding-right: 24px;
    border-right: 1px solid var(--panel-border);
    display: flex;
    flex-direction: column;
}
.control-panel h3 { margin-bottom: 24px; color: var(--text-primary); font-size: 16px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;}
.control-group { margin-bottom: 32px; }
.control-group label { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.5px; }

select {
    width: 100%;
    padding: 14px 16px;
    background: #FFFFFF;
    color: var(--text-primary);
    border: 1px solid var(--panel-border);
    border-radius: var(--radius-md);
    outline: none;
    font-size: 15px;
    cursor: pointer;
    box-shadow: inset 0 1px 2px rgba(0,0,0,0.02);
    transition: var(--transition);
}
select:focus { border-color: var(--system-blue); box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.2); }
.action-buttons { display: flex; flex-direction: column; gap: 16px; margin-top: auto;}
.action-buttons button { padding: 16px; font-size: 16px; }

/* Board Panel */
.board-panel {
    flex: 2;
    padding: 24px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
}
.q-text {
    font-size: 48px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 56px;
    line-height: 1.3;
    letter-spacing: -1px;
}
.options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 24px;
    width: 100%;
    max-width: 900px;
}
.option-card {
    background: #FFFFFF;
    border: 1px solid var(--panel-border);
    padding: 28px;
    border-radius: var(--radius-lg);
    font-size: 24px;
    font-weight: 500;
    box-shadow: 0 4px 12px rgba(0,0,0,0.03);
    transition: var(--transition);
}

/* Winner Overlay */
.winner-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 10;
    opacity: 1;
    transition: opacity 0.4s ease;
    border-radius: var(--radius-lg);
}
.winner-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}
.winner-card {
    background: #FFFFFF;
    border: 1px solid var(--panel-border);
    padding: 60px 80px;
    border-radius: 32px;
    text-align: center;
    box-shadow: 0 20px 40px rgba(0,0,0,0.08);
    transform: scale(1);
    animation: popIn 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}
@keyframes popIn {
    0% { transform: scale(0.8); opacity: 0; }
    100% { transform: scale(1); opacity: 1; }
}
.winner-card h3 { color: var(--system-green); font-size: 24px; margin-bottom: 12px; font-weight: 600;}
.winner-card h1 { font-size: 64px; font-weight: 800; margin-bottom: 24px; letter-spacing: -1.5px; color: var(--text-primary);}
.answer-result { font-size: 28px; font-weight: 600; }
.answer-result.correct { color: var(--system-green); }
.answer-result.wrong { color: var(--system-red); }

/* Leaderboard */
.leaderboard-panel {
    width: 320px;
    padding-left: 24px;
    border-left: 1px solid var(--panel-border);
}
.leaderboard-panel h3 { margin-bottom: 24px; color: var(--text-primary); font-size: 16px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.5px;}
.leaderboard-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}
.team-score-card {
    background: #FFFFFF;
    border: 1px solid var(--panel-border);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 8px rgba(0,0,0,0.02);
    transition: var(--transition);
}
.team-score-card:hover { transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0,0,0,0.06); }
.team-name { font-weight: 600; font-size: 16px; color: var(--text-primary); }
.team-score { font-family: "SF Pro Rounded", "SF Pro Display", monospace; font-size: 24px; font-weight: 700; color: var(--system-blue); }

/* Tables */
table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin-top: 16px;
    background: #FFFFFF;
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--panel-border);
}
th, td {
    padding: 14px 16px;
    text-align: left;
    vertical-align: middle;
    border-bottom: 1px solid var(--panel-border);
}
th {
    background: rgba(0, 0, 0, 0.02);
    font-weight: 600;
    font-size: 13px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
tr:last-child td { border-bottom: none; }
tr:hover td { background: rgba(0, 0, 0, 0.01); }