* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    overflow-y: scroll;
}

:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --error-color: #ef4444;
    --success-color: #10b981;
    --light-bg: #f9fafb;
    --white: #ffffff;
    --text-dark: #111827;
    --text-light: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
        sans-serif;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-dark);
}

.container {
    width: 100%;
    max-width: 1200px;
    padding: 20px;
}

/* Pages */
.page {
    display: none;
    animation: fadeIn 0.3s ease-in;
}

.page.active {
    display: block;
}

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

/* Login Page */
.login-box {
    background: var(--white);
    border-radius: 12px;
    padding: 40px;
    box-shadow: var(--shadow);
    max-width: 400px;
    margin: 0 auto;
}

.login-box h1 {
    font-size: 28px;
    margin-bottom: 8px;
    color: var(--text-dark);
    text-align: center;
}

.subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 30px;
    font-size: 14px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-dark);
    font-size: 14px;
}

.form-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    transition: border-color 0.3s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-group input::placeholder {
    color: var(--text-light);
}

/* Buttons */
.btn {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    margin-top: 10px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(99, 102, 241, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: var(--light-bg);
    color: var(--text-dark);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--border-color);
}

/* Messages */
.error-message {
    color: var(--error-color);
    margin-top: 15px;
    padding: 12px;
    background: rgba(239, 68, 68, 0.1);
    border-radius: 8px;
    display: none;
    font-size: 14px;
    border-left: 4px solid var(--error-color);
}

.error-message.show {
    display: block;
    animation: shake 0.5s;
}

/* Low balance warning banner */
.low-balance-warning {
    background: #fffbeb;
    color: #92400e;
    border: 1px solid #f59e0b;
    border-left: 4px solid #f59e0b;
    border-radius: 8px;
    padding: 12px 16px;
    margin-bottom: 16px;
    font-size: 14px;
    font-weight: 500;
}

.low-balance-warning.hidden {
    display: none;
}

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

/* Spinner */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(99, 102, 241, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 0.8s linear infinite;
    margin-left: 10px;
}

.spinner.hidden {
    display: none;
}

.btn-admin.hidden {
    display: none;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Sheet Tabs */
.sheet-tabs-wrapper {
    display: flex;
    align-items: center;
    gap: 4px;
    margin-bottom: 20px;
}

.scroll-tab-btn {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    padding: 0;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    background: var(--light-bg);
    color: var(--text-dark);
    font-size: 20px;
    line-height: 1;
    cursor: pointer;
    transition: all 0.2s;
    display: none;
}

.scroll-tab-btn.visible {
    display: flex;
    align-items: center;
    justify-content: center;
}

.scroll-tab-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.sheet-tabs {
    display: flex;
    flex-wrap: nowrap;
    gap: 8px;
    overflow-x: hidden;
    scroll-behavior: smooth;
    flex: 1;
}

.sheet-tab {
    padding: 8px 16px;
    border: 2px solid var(--border-color);
    border-radius: 6px;
    background: var(--light-bg);
    color: var(--text-dark);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.sheet-tab:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.sheet-tab.active {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-color: transparent;
    color: var(--white);
}

/* Tasks Page */
.tasks-container {
    background: var(--white);
    border-radius: 12px;
    padding: 40px;
    box-shadow: var(--shadow);
    max-width: 800px;
    margin: 0 auto;
    height: 600px;
    overflow-y: auto;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 2px solid var(--border-color);
}

.header h1 {
    font-size: 24px;
    color: var(--text-dark);
}

.tasks-content h2 {
    font-size: 18px;
    margin-bottom: 20px;
    color: var(--text-dark);
}

.tasks-list {
    list-style: none;
}

.task-item {
    background: var(--light-bg);
    padding: 16px;
    margin-bottom: 12px;
    border-radius: 8px;
    border-left: 4px solid var(--primary-color);
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.task-item:hover {
    background: #f3f4f6;
    transform: translateX(5px);
    transition: all 0.3s;
}

.task-item p {
    color: var(--text-dark);
    line-height: 1.6;
    word-wrap: break-word;
}

.task-row {
    display: flex;
    gap: 12px;
    align-items: flex-start;
}

.task-box {
    flex: 1;
    color: var(--text-dark);
    line-height: 1.6;
    word-wrap: break-word;
}

.note-box {
    flex: 1;
    background: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 8px 12px;
    color: var(--text-light);
    font-size: 13px;
    line-height: 1.5;
    word-wrap: break-word;
}

.btn-delete-task {
    flex-shrink: 0;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--error-color);
    font-size: 16px;
    padding: 4px 8px;
    border-radius: 4px;
    transition: background 0.2s;
    line-height: 1;
    align-self: center;
}

.btn-delete-task:hover {
    background: rgba(239, 68, 68, 0.1);
}

.btn-edit-task {
    flex-shrink: 0;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-light);
    font-size: 16px;
    padding: 4px 8px;
    border-radius: 4px;
    transition: background 0.2s;
    line-height: 1;
    align-self: center;
}

.btn-edit-task:hover {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
}

.btn-move-task-up,
.btn-move-task-down {
    flex-shrink: 0;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text-light);
    font-size: 18px;
    padding: 4px 8px;
    border-radius: 4px;
    transition: background 0.2s;
    line-height: 1;
    align-self: center;
}

.btn-move-task-up:disabled,
.btn-move-task-down:disabled {
    opacity: 0.3;
    cursor: default;
}

.btn-move-task-up:not(:disabled):hover {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
}

.btn-move-task-down:not(:disabled):hover {
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-color);
}

.no-tasks {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-light);
    font-size: 16px;
}

/* Settings footer */
.tasks-footer {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 16px;
}

.btn-settings {
    background: rgba(255, 255, 255, 0.15);
    color: var(--white);
    border: 2px solid rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(4px);
}

.btn-settings:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: var(--white);
}

.btn-delete-category {
  background: rgba(255, 255, 255, 0.15);
  color: var(--white);
  border: 2px solid rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(4px);
}

.btn-delete-category:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: var(--white);
}

.btn-new-category {
    background: rgba(255, 255, 255, 0.15);
    color: var(--white);
    border: 2px solid rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(4px);
}

.btn-new-category:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: var(--white);
}

.btn-new-task {
    background: rgba(255, 255, 255, 0.15);
    color: var(--white);
    border: 2px solid rgba(255, 255, 255, 0.5);
    backdrop-filter: blur(4px);
}

.btn-new-task:hover {
    background: rgba(255, 255, 255, 0.25);
    border-color: var(--white);
}

.btn-admin {
    background: rgba(251, 191, 36, 0.2);
    color: var(--white);
    border: 2px solid rgba(251, 191, 36, 0.6);
    backdrop-filter: blur(4px);
}

.btn-admin:hover {
    background: rgba(251, 191, 36, 0.35);
    border-color: rgba(251, 191, 36, 0.9);
}

/* Modal select */
.modal-select {
    width: 100%;
    padding: 12px;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    font-size: 14px;
    background: var(--white);
    color: var(--text-dark);
    transition: border-color 0.3s;
    cursor: pointer;
}

.modal-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* Modal */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    animation: fadeIn 0.2s ease-in;
}

.modal-overlay.hidden {
    display: none;
}

.modal-box {
    background: var(--white);
    border-radius: 12px;
    padding: 32px;
    box-shadow: var(--shadow);
    width: 100%;
    max-width: 400px;
    animation: fadeIn 0.2s ease-in;
}

.modal-box h2 {
    font-size: 20px;
    margin-bottom: 24px;
    color: var(--text-dark);
}

.modal-error {
    color: var(--error-color);
    font-size: 13px;
    min-height: 18px;
    margin-bottom: 8px;
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 16px;
}

.btn-primary-small {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: 10px 24px;
}

.btn-primary-small:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.btn-primary-small:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-delete-confirm {
    background: var(--error-color);
    color: var(--white);
    padding: 10px 24px;
}

.btn-delete-confirm:hover {
    background: #dc2626;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(239, 68, 68, 0.4);
}

.confirm-delete-msg {
    color: var(--text-dark);
    font-size: 14px;
    line-height: 1.5;
    margin-bottom: 8px;
}

/* Settings menu modal – stacked action buttons */
.settings-menu-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 16px;
}

.settings-menu-btn {
    width: 100%;
    text-align: center;
}

/* Add User Success Modal */
.add-user-success-box {
    max-width: 480px;
}

.add-user-success-msg {
    color: var(--text-dark);
    font-size: 14px;
    line-height: 1.5;
    margin-bottom: 16px;
}

.add-user-workbook-info {
    background: var(--light-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 14px 16px;
    margin-bottom: 16px;
}

.add-user-info-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 8px;
}

.add-user-info-row:last-child {
    margin-bottom: 0;
}

.add-user-info-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    white-space: nowrap;
}

.add-user-info-value {
    font-size: 13px;
    font-family: 'Courier New', Courier, monospace;
    color: var(--primary-color);
    word-break: break-all;
    font-weight: 600;
}

.add-user-workbook-link {
    font-size: 13px;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.add-user-workbook-link:hover {
    text-decoration: underline;
}

.add-user-reminder {
    display: flex;
    gap: 10px;
    align-items: flex-start;
    background: rgba(251, 191, 36, 0.12);
    border: 1px solid rgba(251, 191, 36, 0.5);
    border-radius: 8px;
    padding: 12px 14px;
    font-size: 13px;
    color: var(--text-dark);
    line-height: 1.5;
    margin-bottom: 4px;
}

.add-user-reminder-icon {
    flex-shrink: 0;
    font-size: 16px;
    margin-top: 1px;
}

/* User Credit List Modal */
.user-credit-list-box {
    max-width: 480px;
}

.user-credit-list {
    max-height: 320px;
    overflow-y: auto;
    margin-bottom: 8px;
}

.user-credit-loading {
    color: var(--text-light);
    font-size: 14px;
    padding: 12px 0;
}

.user-credit-row {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 0;
    border-bottom: 1px solid var(--border-color);
}

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

.user-credit-name {
    flex: 1;
    font-size: 14px;
    color: var(--text-dark);
    font-weight: 500;
    word-break: break-all;
}

.user-credit-value {
    font-size: 14px;
    color: var(--primary-color);
    font-weight: 600;
    min-width: 48px;
    text-align: right;
}

.btn-add-credit {
    flex-shrink: 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    border: none;
    border-radius: 6px;
    width: 28px;
    height: 28px;
    font-size: 18px;
    line-height: 1;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.2s, transform 0.2s;
}

.btn-add-credit:hover {
    opacity: 0.85;
    transform: translateY(-1px);
}

/* Add Credit Modal */
.add-credit-for-user {
    font-size: 14px;
    color: var(--text-light);
    margin-bottom: 16px;
}

/* Responsive */
@media (max-width: 600px) {
    .login-box {
        padding: 30px 20px;
    }

    .login-box h1 {
        font-size: 24px;
    }

    .tasks-container {
        padding: 20px;
    }

    .header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .header h1 {
        font-size: 20px;
    }

    .btn-secondary {
        width: 100%;
    }

    .task-row {
        flex-direction: column;
    }
}