:root {
    --bg-color: #f4f6f8;
    --text-color: #333;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --card-bg: rgba(255, 255, 255, 0.5);
    --border-color: rgba(0, 0, 0, 0.1);
    --read-bg: #fff;
    --pause-bg: rgba(255, 255, 255, 0.8);
    --pause-icon-color: rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] {
    --bg-color: #1a1a2e;
    --text-color: #e0e0e0;
    --glass-bg: rgba(20, 20, 35, 0.8);
    --card-bg: rgba(30, 30, 50, 0.8);
    --border-color: rgba(255, 255, 255, 0.1);
    --read-bg: #161625;
    --pause-bg: rgba(0, 0, 0, 0.6);
    --pause-icon-color: rgba(255, 255, 255, 0.4);
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s, color 0.3s;
}

.back-link {
    position: absolute;
    top: 20px;
    left: 20px;
    text-decoration: none;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    opacity: 0.7;
    transition: opacity 0.2s;
    z-index: 100;
}
.back-link:hover { opacity: 1; }

.glass {
    background: var(--glass-bg);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.1);
    border: 1px solid var(--border-color);
}

.btn {
    padding: 15px 40px;
    font-size: 1.2rem;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    background: var(--primary-color, #467230);
    color: white;
    box-shadow: 0 4px 15px rgba(70, 114, 48, 0.3);
}
.btn.outline {
    background: transparent;
    color: var(--primary-color, #467230);
    border: 2px solid var(--primary-color, #467230);
    box-shadow: none;
}
.btn.outline:hover {
    background: var(--primary-color, #467230);
    color: white;
}
.btn.small {
    padding: 8px 16px;
    font-size: 1rem;
    border-radius: 8px;
}

.app-container {
    width: 95%;
    max-width: 900px;
    height: 90vh;
    border-radius: 20px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    position: relative;
    padding: 30px;
}

.screen {
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    width: 100%;
    transition: opacity 0.3s ease;
}

.screen.hidden {
    display: none !important;
}

.hidden {
    display: none !important;
}

.screen.active {
    display: flex;
    opacity: 1;
}

h1 {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.settings-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 30px;
    background: var(--card-bg);
    padding: 20px;
    border-radius: 15px;
    width: 100%;
    max-width: 600px;
    border: 1px solid var(--border-color);
}

.setting-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.setting-title {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--text-color);
    opacity: 0.8;
}

.custom-select {
    width: 100%;
    padding: 10px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
    outline: none;
    cursor: pointer;
}

/* Экран Списывание */
#screen-paper {
    justify-content: flex-start;
}

.read-header {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 10px;
    position: sticky;
    top: 0;
    background: var(--glass-bg);
    padding: 10px;
    border-radius: 10px;
    z-index: 10;
}

.timer {
    font-size: 1.5rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    background: var(--card-bg);
    padding: 5px 15px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.read-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.examples-list-container {
    width: 100%;
    overflow-y: auto;
    padding-right: 10px;
    font-size: 18px;
    line-height: 2;
    column-count: 2;
    column-gap: 40px;
}

@media (max-width: 600px) {
    .examples-list-container {
        column-count: 1;
    }
}

.example-item {
    break-inside: avoid;
    margin-bottom: 5px;
    display: flex;
    justify-content: space-between;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 2px;
}

.example-num {
    opacity: 0.5;
    margin-right: 10px;
    font-size: 14px;
    width: 30px;
    display: inline-block;
}

.example-eq {
    flex: 1;
    font-weight: 500;
}

.example-ans {
    color: var(--primary-color);
    font-weight: bold;
    min-width: 40px;
    text-align: right;
}

/* Экран цифровой ввод */
.digital-play-area {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 100%;
    flex: 1;
    position: relative;
}

.digital-equation-container {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 4rem;
    font-weight: 700;
}

.digital-input {
    font-size: 4rem;
    font-weight: 700;
    width: 150px;
    text-align: center;
    background: transparent;
    border: none;
    border-bottom: 4px solid var(--text-color);
    color: var(--text-color);
    outline: none;
    padding: 0;
}

.digital-input:focus {
    border-bottom-color: var(--primary-color);
}

.digital-input.error {
    color: #E74C3C;
    border-bottom-color: #E74C3C;
    animation: shake 0.3s ease-in-out;
}

.digital-input.success {
    color: #2ECC71;
    border-bottom-color: #2ECC71;
}

.digital-feedback {
    font-size: 2rem;
    color: #E74C3C;
    margin-top: 20px;
    font-weight: bold;
    height: 40px;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-10px); }
    75% { transform: translateX(10px); }
}

/* Результаты */
.quiz-result-box {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    border: 1px solid var(--border-color);
    width: 100%;
    max-width: 500px;
}

.stat-row {
    display: flex;
    justify-content: space-between;
    padding: 15px 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 1.2rem;
}

.stat-row:last-child {
    border-bottom: none;
}


.theme-toggle { position: absolute; top: 20px; right: 20px; width: 50px; height: 50px; border-radius: 50%; border: 1px solid var(--border-color); background: var(--glass-bg); color: var(--text-color); display: flex; justify-content: center; align-items: center; font-size: 1.5rem; cursor: pointer; z-index: 100; }

.history-container {
    overflow-y: auto;
    max-height: 200px;
}

.history-container h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 10px;
    opacity: 0.8;
}

.history-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--card-bg);
    border-radius: 10px;
    overflow: hidden;
    font-size: 0.9rem;
    border: 1px solid var(--border-color);
}

.history-table th,
.history-table td {
    padding: 8px 12px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.history-table th {
    background: var(--card-bg);
    font-weight: 600;
    opacity: 0.8;
}

.history-table tr:last-child td {
    border-bottom: none;
}