:root {
    --font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --primary-text: #ffffff;
    --secondary-text: #e0e0e0;
    --disabled-text: #a0a0a0;
    --accent-color: #007aff;
    --accent-hover: #3395ff;
    --success-color: #34c759;
    --warning-color: #ff9500;
    --danger-color: #ff3b30;
    --glass-bg: rgba(30, 30, 30, 0.5);
    --glass-border: rgba(255, 255, 255, 0.2);
    --item-bg: rgba(255, 255, 255, 0.08);
    --item-hover-bg: rgba(255, 255, 255, 0.15);
    --border-radius: 12px;
    --transition-speed: 0.3s;
}

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

body {
    font-family: var(--font-family);
    color: var(--primary-text);
    overflow: hidden;
    height: 100vh;
    width: 100vw;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.background-gradient {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: linear-gradient(-45deg, #ee7752, #e73c7e, #23a6d5, #23d5ab);
    background-size: 400% 400%;
    animation: gradient 20s ease infinite;
}

@keyframes gradient {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

.screen {
    width: 100%;
    height: 100%;
    display: none;
    transition: opacity var(--transition-speed) ease;
}

.screen.active {
    display: flex;
}

.glass-container {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-radius: var(--border-radius);
    border: 1px solid var(--glass-border);
    box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
}

/* 登录界面 */
#login-screen {
    justify-content: center;
    align-items: center;
}

.login-content {
    text-align: center;
    padding: 40px;
    width: 90%;
    max-width: 400px;
}

.app-title {
    font-size: 48px;
    font-weight: 700;
    letter-spacing: 2px;
}
.app-title-sidebar {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 30px;
    padding: 0 20px;
}

.app-subtitle {
    font-size: 18px;
    font-weight: 300;
    color: var(--secondary-text);
    margin-top: 10px;
    margin-bottom: 30px;
}

.input-group {
    display: flex;
    gap: 10px;
}

.input-group input {
    flex-grow: 1;
    background: var(--item-bg);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 12px 15px;
    font-size: 16px;
    color: var(--primary-text);
    outline: none;
    transition: all var(--transition-speed) ease;
}

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

.input-group input:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.3);
}

.input-group button {
    padding: 12px 20px;
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
}

.input-group button:hover {
    background-color: var(--accent-hover);
}

.error-message {
    color: var(--danger-color);
    margin-top: 15px;
    height: 20px;
}

/* 主应用布局 */
#app-screen {
    padding: 20px;
    gap: 20px;
}

.sidebar {
    width: 240px;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
}

.sidebar nav {
    display: flex;
    flex-direction: column;
    gap: 10px;
    flex-grow: 1;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 15px;
    padding: 12px 20px;
    text-decoration: none;
    color: var(--secondary-text);
    border-radius: 8px;
    transition: all var(--transition-speed) ease;
}

.nav-link:hover {
    background-color: var(--item-hover-bg);
    color: var(--primary-text);
}

.nav-link.active {
    background-color: var(--accent-color);
    color: white;
    font-weight: 500;
}

.nav-link svg {
    width: 20px;
    height: 20px;
}

.sidebar-footer {
    padding: 20px;
    border-top: 1px solid var(--glass-border);
}

.countdown-title {
    font-size: 14px;
    color: var(--secondary-text);
    margin-bottom: 8px;
}

#countdown-display {
    font-size: 16px;
    font-weight: 500;
    text-align: center;
}

.main-content {
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    position: relative;
    overflow: hidden;
}

.view {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-speed) ease, visibility var(--transition-speed) ease;
    display: flex;
    flex-direction: column;
}

.view.active {
    opacity: 1;
    visibility: visible;
}

.view-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    border-bottom: 1px solid var(--glass-border);
    flex-shrink: 0;
}

.view-header h2 {
    font-weight: 500;
}

.date-selector {
    display: flex;
    align-items: center;
    gap: 10px;
}
.date-selector button, .date-selector input {
    background: transparent;
    border: 1px solid var(--glass-border);
    color: var(--primary-text);
    border-radius: 6px;
    padding: 8px 12px;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
}
.date-selector button:hover {
    background-color: var(--item-hover-bg);
}

#current-date-picker::-webkit-calendar-picker-indicator {
    filter: invert(1);
}

.main-action-btn {
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: 8px;
    padding: 10px 18px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color var(--transition-speed) ease;
}

.main-action-btn:hover {
    background-color: var(--accent-hover);
}

.list-container {
    flex-grow: 1;
    overflow-y: auto;
    padding: 20px;
}

/* Todo Item */
.todo-item {
    background: var(--item-bg);
    border: 1px solid transparent;
    border-radius: var(--border-radius);
    padding: 15px;
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 12px;
    transition: all var(--transition-speed) ease;
}
.todo-item:hover {
    background: var(--item-hover-bg);
    border-color: var(--glass-border);
}
.todo-item[data-status="in_progress"] {
    border-left: 4px solid var(--accent-color);
}
.todo-item[data-status="completed"] {
    border-left: 4px solid var(--success-color);
}
.todo-item[data-status="completed"] .todo-content {
    text-decoration: line-through;
    color: var(--disabled-text);
}

.status-checkbox {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    border: 2px solid var(--secondary-text);
    cursor: pointer;
    transition: all var(--transition-speed) ease;
    flex-shrink: 0;
}
.status-checkbox.completed {
    background-color: var(--success-color);
    border-color: var(--success-color);
}

.todo-details {
    flex-grow: 1;
}
.todo-content {
    font-size: 16px;
    font-weight: 400;
}
.todo-category {
    font-size: 12px;
    padding: 3px 8px;
    border-radius: 10px;
    display: inline-block;
    margin-top: 8px;
}

.todo-actions {
    display: flex;
    gap: 8px;
    opacity: 0;
    transition: opacity var(--transition-speed) ease;
}
.todo-item:hover .todo-actions {
    opacity: 1;
}
.todo-actions button {
    background: none;
    border: none;
    color: var(--secondary-text);
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-speed) ease;
}
.todo-actions button:hover {
    background: var(--item-hover-bg);
    color: var(--primary-text);
}

/* Modal */
.modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition-speed) ease, visibility var(--transition-speed) ease;
}

.modal-backdrop.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    width: 90%;
    max-width: 500px;
    padding: 30px;
    transform: scale(0.9);
    transition: transform var(--transition-speed) ease;
}
.modal-backdrop.active .modal-content {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.modal-header h3 {
    font-size: 20px;
    font-weight: 500;
}

.close-modal-btn {
    background: none;
    border: none;
    color: var(--secondary-text);
    font-size: 24px;
    cursor: pointer;
}

.modal-body .form-group {
    margin-bottom: 15px;
}

.modal-body label {
    display: block;
    margin-bottom: 8px;
    color: var(--secondary-text);
    font-size: 14px;
}

.modal-body input, .modal-body select, .modal-body textarea {
    width: 100%;
    background: var(--item-bg);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 15px;
    color: var(--primary-text);
}
.modal-body textarea {
    resize: vertical;
    min-height: 80px;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: 25px;
}

.modal-footer button {
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    font-size: 15px;
    transition: all var(--transition-speed) ease;
}

.modal-footer .btn-secondary {
    background: var(--item-bg);
    color: var(--primary-text);
}
.modal-footer .btn-secondary:hover {
    background: var(--item-hover-bg);
}

.modal-footer .btn-primary {
    background: var(--accent-color);
    color: white;
}
.modal-footer .btn-primary:hover {
    background: var(--accent-hover);
}
.modal-footer .btn-danger {
    background-color: var(--danger-color);
    color: white;
}

/* Heatmap */
#heatmap-container {
    padding: 20px;
    border-top: 1px solid var(--glass-border);
}

#heatmap {
    display: grid;
    grid-template-rows: repeat(7, 1fr);
    grid-auto-flow: column;
    gap: 4px;
}
#heatmap-container h3 {
    font-weight: 500;
    margin-bottom: 15px;
}
.heatmap-day {
    width: 15px;
    height: 15px;
    background-color: var(--item-bg);
    border-radius: 3px;
    opacity: 0.5;
}
.heatmap-day[data-level="1"] { background-color: #0e4429; opacity: 1; }
.heatmap-day[data-level="2"] { background-color: #006d32; opacity: 1; }
.heatmap-day[data-level="3"] { background-color: #26a641; opacity: 1; }
.heatmap-day[data-level="4"] { background-color: #39d353; opacity: 1; }


/* Review View */
.review-form, .settings-form {
    padding: 20px;
    overflow-y: auto;
}
.review-selector {
    padding: 8px 12px;
    background-color: var(--item-bg);
    border-radius: 8px;
}
#review-period-selector {
    background: transparent;
    border: none;
    color: var(--primary-text);
    font-size: 15px;
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.3);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.5);
}