:root {
    color-scheme: light;
    --bg: #f0f2f5;
    --surface: #ffffff;
    --surface-alt: #f8f9fa;
    --text: #1f2937;
    --muted: #6b7280;
    --heading: #111827;
    --border: #dfe4ea;
    --input-bg: #ffffff;
    --input-border: #cbd5e1;
    --input-text: #111827;
    --primary: #007bff;
    --primary-hover: #0056b3;
    --success: #28a745;
    --danger: #dc3545;
    --warning: #e0a800;
    --shadow: rgba(15, 23, 42, 0.12);
    --button-text: #ffffff;
}

:root[data-theme="dark"] {
    color-scheme: dark;
    --bg: #0f172a;
    --surface: #111827;
    --surface-alt: #172033;
    --text: #f3f4f6;
    --muted: #cbd5e1;
    --heading: #f8fafc;
    --border: #334155;
    --input-bg: #111827;
    --input-border: #475569;
    --input-text: #f8fafc;
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --success: #34d399;
    --danger: #f87171;
    --warning: #fbbf24;
    --shadow: rgba(2, 6, 23, 0.45);
    --button-text: #ffffff;
}

/* Общие настройки для всей страницы */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg);
    color: var(--text);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    transition: background-color 0.2s ease, color 0.2s ease;
}

/* Наша белая карточка-контейнер */
.container {
    background: var(--surface);
    color: var(--text);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 8px 24px var(--shadow);
    width: 100%;
    max-width: 400px;
    border: 1px solid var(--border);
}

h2 {
    margin-top: 0;
    color: var(--heading);
    text-align: center;
}

p {
    color: var(--muted);
    font-size: 14px;
    text-align: center;
    margin-bottom: 25px;
}

/* Отступы между полями ввода */
.form-group {
    margin-bottom: 20px;
    text-align: left;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text);
    font-size: 14px;
}

/* Красивое оформление полей ввода и выпадающего списка */
input[type="text"],
input[type="password"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--input-border);
    border-radius: 6px;
    font-size: 14px;
    box-sizing: border-box;
    transition: border-color 0.3s;
    background: var(--input-bg);
    color: var(--input-text);
}

input::placeholder,
textarea::placeholder {
    color: var(--muted);
}

/* Эффект синего свечения при клике на поле */
input:focus,
select:focus,
textarea:focus {
    border-color: var(--primary);
    outline: none;
}

/* Кнопка */
button {
    width: 100%;
    background-color: var(--primary);
    color: var(--button-text);
    border: none;
    padding: 12px;
    font-size: 15px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    margin-top: 10px;
    box-shadow: 0 2px 6px rgba(0, 123, 255, 0.16);
}

button:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
}

button:active {
    transform: translateY(0);
}

button[style*="background-color: #6c757d"] {
    box-shadow: none;
}

button[style*="background-color: #6f42c1"] {
    box-shadow: 0 2px 6px rgba(111, 66, 193, 0.2);
}

button[style*="background-color: #28a745"] {
    box-shadow: 0 2px 6px rgba(40, 167, 69, 0.2);
}

.reset-modal {
    position: fixed;
    inset: 0;
    background: rgba(2, 6, 23, 0.6);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.reset-modal-content {
    background: var(--surface);
    color: var(--text);
    width: 100%;
    max-width: 420px;
    border-radius: 12px;
    padding: 24px;
    box-shadow: 0 16px 40px rgba(2, 6, 23, 0.28);
    border: 1px solid var(--border);
    position: relative;
}

.reset-modal-close {
    position: absolute;
    top: 10px;
    right: 12px;
    background: transparent;
    color: var(--muted);
    width: auto;
    padding: 0;
    margin: 0;
    border: none;
    box-shadow: none;
    font-size: 24px;
    cursor: pointer;
}

.reset-modal-description {
    margin: 0 0 16px;
    text-align: left;
}

.reset-actions {
    display: flex;
    gap: 10px;
    margin-top: 6px;
}

.reset-actions button {
    flex: 1;
    margin-top: 0;
}

.reset-cancel-btn {
    background-color: #6c757d;
}

.reset-cancel-btn:hover {
    background-color: #5a6268;
}

.footer-text {
    margin-top: 20px;
    font-size: 13px;
}

.footer-text a {
    color: var(--primary);
    text-decoration: none;
}

.footer-text a:hover {
    text-decoration: underline;
}

.theme-toggle {
    width: auto;
    margin: 0;
    padding: 8px 12px;
    font-size: 14px;
    background-color: var(--surface-alt);
    color: var(--text);
    border: 1px solid var(--border);
    box-shadow: none;
}

.theme-toggle:hover {
    background-color: var(--border);
    color: var(--heading);
}

.admin-table th {
    background-color: var(--surface-alt);
    color: var(--heading);
}

.admin-table td {
    background-color: var(--surface);
    color: var(--text);
    border-color: var(--border);
}

.badge {
    background-color: var(--primary);
    color: var(--button-text);
}

.admin-nav-btn {
    width: auto;
    margin: 0;
    padding: 8px 16px;
    border-radius: 6px;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.summary-status-pill {
    display: inline-block;
    padding: 3px 8px;
    border-radius: 999px;
    font-weight: 700;
    font-size: 12px;
    line-height: 1.4;
    border: 1px solid transparent;
}

.summary-status-pending {
    background: rgba(245, 158, 11, 0.18);
    color: #fbbf24;
    border-color: rgba(245, 158, 11, 0.3);
}

.summary-status-approved {
    background: rgba(34, 197, 94, 0.16);
    color: #86efac;
    border-color: rgba(34, 197, 94, 0.3);
}

.summary-status-rejected {
    background: rgba(239, 68, 68, 0.16);
    color: #fda4af;
    border-color: rgba(239, 68, 68, 0.3);
}

.summary-status-empty {
    background: var(--surface-alt);
    color: var(--muted);
    border-color: var(--border);
}

.admin-toast-container {
    position: fixed;
    right: 18px;
    bottom: 18px;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-width: 360px;
    pointer-events: none;
}

.admin-toast {
    background: var(--surface);
    color: var(--text);
    border: 1px solid var(--border);
    border-left: 4px solid var(--primary);
    border-radius: 10px;
    padding: 12px 14px;
    box-shadow: 0 10px 24px rgba(2, 6, 23, 0.2);
    animation: toastSlideIn 0.25s ease-out;
    pointer-events: auto;
}

.admin-toast.success {
    border-left-color: var(--success);
}

.admin-toast.warning {
    border-left-color: var(--warning);
}

.admin-toast-title {
    font-weight: 700;
    margin-bottom: 4px;
}

.admin-toast-message {
    font-size: 13px;
    color: var(--muted);
    line-height: 1.4;
}

@keyframes toastSlideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.student-discipline-item:hover,
.admin-student-card:hover {
    background: var(--surface-alt) !important;
    color: var(--heading) !important;
    border-color: var(--primary) !important;
}

.modal-content,
#student-action-modal > div,
#admin-credentials-modal > div,
#check-solution-modal > div,
#student-modal > div {
    background: var(--surface) !important;
    color: var(--text) !important;
    border: 1px solid var(--border) !important;
}

#student-action-modal,
#admin-credentials-modal,
#check-solution-modal,
#student-modal {
    background: rgba(2, 6, 23, 0.6) !important;
}

:root[data-theme="dark"] .admin-section,
:root[data-theme="dark"] #group-form-container,
:root[data-theme="dark"] #selected-group-section,
:root[data-theme="dark"] #group-requests-panel,
:root[data-theme="dark"] #sheet-table-container,
:root[data-theme="dark"] #admin-groups-list > div,
:root[data-theme="dark"] #group-disciplines-list > div,
:root[data-theme="dark"] #group-students-list > div {
    background: var(--surface-alt) !important;
    border-color: var(--border) !important;
    color: var(--text) !important;
}

:root[data-theme="dark"] [style*="background: #ffffff"],
:root[data-theme="dark"] [style*="background: #fff"],
:root[data-theme="dark"] [style*="background-color: #ffffff"],
:root[data-theme="dark"] [style*="background-color: #fff"],
:root[data-theme="dark"] [style*="background: #f8f9fa"],
:root[data-theme="dark"] [style*="background: #f1f3f5"],
:root[data-theme="dark"] [style*="background-color: #f8f9fa"],
:root[data-theme="dark"] [style*="background-color: #f1f3f5"],
:root[data-theme="dark"] [style*="background: #f8fbff"],
:root[data-theme="dark"] [style*="background-color: #f8fbff"],
:root[data-theme="dark"] [style*="background: #fff8f0"],
:root[data-theme="dark"] [style*="background-color: #fff8f0"],
:root[data-theme="dark"] [style*="background: #fff3e0"],
:root[data-theme="dark"] [style*="background-color: #fff3e0"],
:root[data-theme="dark"] [style*="background-color: #e9ecef"],
:root[data-theme="dark"] [style*="background-color: #fefefe"],
:root[data-theme="dark"] [style*="background-color: #f8fbff"],
:root[data-theme="dark"] [style*="background-color: #f3f7ff"] {
    background: var(--surface-alt) !important;
    border-color: var(--border) !important;
}

:root[data-theme="dark"] [style*="background: linear-gradient(135deg, #f8fbff 0%, #f3f7ff 100%)"],
:root[data-theme="dark"] [style*="background: linear-gradient(135deg, #fff8f0 0%, #fff3e0 100%)"],
:root[data-theme="dark"] [style*="background: linear-gradient(135deg, #f8fbff 0%, #f3f7ff 100%)"] {
    background: linear-gradient(135deg, #1e293b 0%, #0f172a 100%) !important;
    border-color: var(--border) !important;
}

:root[data-theme="dark"] .container h1,
:root[data-theme="dark"] .container h2,
:root[data-theme="dark"] .container h3,
:root[data-theme="dark"] .container h4,
:root[data-theme="dark"] .container h5,
:root[data-theme="dark"] .container h6,
:root[data-theme="dark"] .container p,
:root[data-theme="dark"] .container span,
:root[data-theme="dark"] .container label,
:root[data-theme="dark"] .container strong,
:root[data-theme="dark"] .container li,
:root[data-theme="dark"] .container td,
:root[data-theme="dark"] .container th,
:root[data-theme="dark"] .container a {
    color: var(--text) !important;
}

:root[data-theme="dark"] .container [style*="color: #333"],
:root[data-theme="dark"] .container [style*="color: #666"],
:root[data-theme="dark"] .container [style*="color: #555"],
:root[data-theme="dark"] .container [style*="color: #495057"],
:root[data-theme="dark"] .container [style*="color: #6c757d"],
:root[data-theme="dark"] .container [style*="color: #2c3e50"],
:root[data-theme="dark"] .container [style*="color: #888"],
:root[data-theme="dark"] .container [style*="color: #aaa"] {
    color: var(--text) !important;
}

:root[data-theme="dark"] .container [style*="color: #007bff"] {
    color: var(--primary) !important;
}

:root[data-theme="dark"] .container .badge,
:root[data-theme="dark"] .container .theme-toggle,
:root[data-theme="dark"] .container button {
    color: var(--button-text) !important;
}

:root[data-theme="dark"] .container a {
    color: var(--primary) !important;
}

:root[data-theme="dark"] #summary-table th,
:root[data-theme="dark"] #summary-table td,
:root[data-theme="dark"] #summary-table tr {
    background-color: var(--surface) !important;
    color: var(--text) !important;
    border-color: var(--border) !important;
}

:root[data-theme="dark"] #summary-table thead th {
    background-color: var(--surface-alt) !important;
}

:root[data-theme="dark"] .loading-text,
:root[data-theme="dark"] #summary-empty-message,
:root[data-theme="dark"] #pending-users p,
:root[data-theme="dark"] #group-requests-list p,
:root[data-theme="dark"] #group-requests-list table,
:root[data-theme="dark"] #group-requests-list th,
:root[data-theme="dark"] #group-requests-list td,
:root[data-theme="dark"] #student-disciplines-list p,
:root[data-theme="dark"] #student-tasks-list p,
:root[data-theme="dark"] #group-disciplines-list p,
:root[data-theme="dark"] #group-students-list p,
:root[data-theme="dark"] #modal-student-works p,
:root[data-theme="dark"] #sheet-table-container p {
    color: var(--text) !important;
}

:root[data-theme="dark"] #student-action-modal > div,
:root[data-theme="dark"] #admin-credentials-modal > div,
:root[data-theme="dark"] #check-solution-modal > div,
:root[data-theme="dark"] #student-modal > div,
:root[data-theme="dark"] .modal-content {
    box-shadow: 0 16px 40px rgba(2, 6, 23, 0.55) !important;
}

:root[data-theme="dark"] [style*="border: 1px solid #dee2e6"],
:root[data-theme="dark"] [style*="border: 1px solid #ced4da"],
:root[data-theme="dark"] [style*="border: 1px solid #e3e6ea"],
:root[data-theme="dark"] [style*="border: 1px solid #eee"],
:root[data-theme="dark"] [style*="border-top: 1px solid #eee"],
:root[data-theme="dark"] [style*="border-top: 1px solid #eef2f5"],
:root[data-theme="dark"] [style*="border-bottom: 2px solid #eee"],
:root[data-theme="dark"] [style*="border-bottom: 2px solid #dee2e6"] {
    border-color: var(--border) !important;
}

/* Стили для таблиц в админке */
.admin-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 15px;
    margin-bottom: 25px;
    font-size: 14px;
}

.admin-table th, .admin-table td {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: left;
}

.admin-table th {
    background-color: #f2f2f2;
    color: #333;
}

/* Кнопка "Одобрить" */
.btn-approve {
    background-color: #28a745;
    color: white;
    border: none;
    padding: 6px 12px;
    cursor: pointer;
    border-radius: 4px;
    font-weight: bold;
}

.btn-approve:hover {
    background-color: #218838;
}

/* Красивый бейдж группы */
.badge {
    background-color: #007bff;
    color: white;
    padding: 3px 8px;
    border-radius: 12px;
    font-size: 12px;
}

/* Стили для модальных окон кабинета студента */
#student-action-modal {
    backdrop-filter: blur(2px);
}

#student-action-modal > div {
    border: 1px solid #e3e6ea;
    animation: modalFadeIn 0.18s ease-out;
}

#student-action-modal h3 {
    color: #2c3e50;
    font-size: 20px;
    border-bottom: 1px solid #eef2f5;
    padding-bottom: 10px;
}

#student-action-modal input,
#student-action-modal select {
    border: 1px solid #ced4da;
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 14px;
}

#student-action-modal input:focus,
#student-action-modal select:focus {
    border-color: #80bdff;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.15);
}

#student-action-modal button {
    min-width: 110px;
    font-size: 14px;
    margin-top: 0;
}

/* === СТИЛИ ДЛЯ КРАСИВОЙ АДМИНСКОЙ ПАНЕЛИ === */

/* Стили для модального окна смены учетных данных в админке */
#admin-credentials-modal {
    backdrop-filter: blur(2px);
}

#admin-credentials-modal > div {
    border: 1px solid #e3e6ea;
    animation: modalFadeIn 0.18s ease-out;
}

#admin-credentials-modal h3 {
    color: #2c3e50;
    font-size: 20px;
    border-bottom: 1px solid #eef2f5;
    padding-bottom: 10px;
}

#admin-credentials-modal input,
#admin-credentials-modal select {
    border: 1px solid #ced4da;
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 14px;
    transition: all 0.2s ease;
}

#admin-credentials-modal input:focus,
#admin-credentials-modal select:focus {
    border-color: #80bdff;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.15);
}

#admin-credentials-modal button {
    min-width: 110px;
    font-size: 14px;
    margin-top: 0;
    box-shadow: 0 2px 6px rgba(111, 66, 193, 0.2);
    transition: all 0.2s ease;
}

#admin-credentials-modal button:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(111, 66, 193, 0.3);
}

/* Анимация появления модального окна */
@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Стили для модальных окон студента (в админке) */
.modal-content {
    animation: modalFadeIn 0.18s ease-out;
    border: 1px solid #e3e6ea;
}

.modal-content h3 {
    color: #2c3e50;
    border-bottom: 1px solid #eef2f5;
    padding-bottom: 10px;
}

.modal-content input,
.modal-content select {
    border: 1px solid #ced4da;
    border-radius: 8px;
    transition: all 0.2s ease;
}

.modal-content input:focus,
.modal-content select:focus {
    border-color: #80bdff;
    box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.15);
}

/* Красивое оформление карточек студентов */
.admin-table tr {
    transition: all 0.2s ease;
}

.admin-table tbody tr:hover {
    background-color: #f0f7ff;
}

/* Стили для группы студентов */
#group-students-list .admin-table tr {
    cursor: pointer;
    background-color: #fff;
}

#group-students-list .admin-table tr:hover {
    background-color: #e9f5ff;
    box-shadow: 0 1px 3px rgba(0, 123, 255, 0.1);
}

/* Красивые кнопки в админке */
button[style*="background-color: #6f42c1"] {
    box-shadow: 0 2px 6px rgba(111, 66, 193, 0.2);
    transition: all 0.2s ease;
}

button[style*="background-color: #6f42c1"]:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(111, 66, 193, 0.3);
}

button[style*="background-color: #17a2b8"] {
    box-shadow: 0 2px 6px rgba(23, 162, 184, 0.2);
    transition: all 0.2s ease;
}

button[style*="background-color: #17a2b8"]:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(23, 162, 184, 0.3);
}

button[style*="background-color: #ffc107"] {
    box-shadow: 0 2px 6px rgba(255, 193, 7, 0.2);
    transition: all 0.2s ease;
}

button[style*="background-color: #ffc107"]:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(255, 193, 7, 0.3);
}

button[style*="background-color: #dc3545"] {
    box-shadow: 0 2px 6px rgba(220, 53, 69, 0.2);
    transition: all 0.2s ease;
}

button[style*="background-color: #dc3545"]:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(220, 53, 69, 0.3);
}

@keyframes modalFadeIn {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Плавное проявление ошибки при входе */
#login-error-msg {
    animation: errorFadeIn 0.35s ease-out forwards;
}

@keyframes errorFadeIn {
    from {
        opacity: 0;
        transform: translateY(-6px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}