:root {
    --primary-color: #f5a623;
    --primary-dark: #cc840f;
    --primary-light: #f9e7c3;
    --text-main: #202124;
    --text-light: #5f6368;
    --bg-body: #ffffff;
    --card-bg: #f5f5f5;
    --border-color: #dddddd;
    --fab-color: #f5a623;
    --editor-active-color: #f5a623;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: 'Roboto', Arial, sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    display: flex; flex-direction: column;
    height: 100vh; overflow: hidden;
}

/* Header */
.app-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 8px 16px; height: 64px; border-bottom: 1px solid var(--border-color);
    background-color: #ffffff; z-index: 1000; box-shadow: 0 1px 2px rgba(0,0,0,0.05);
}
.header-left { display: flex; align-items: center; gap: 16px; }
.icon-btn {
    background: none; border: none; color: var(--text-light); cursor: pointer;
    padding: 12px; border-radius: 50%; display: flex; align-items: center; justify-content: center;
    transition: background-color 0.2s;
}
.icon-btn:hover { background-color: rgba(0,0,0,0.05); color: var(--text-main); }
.sync-btn {
    display: flex; align-items: center; gap: 8px; background-color: var(--border-color); color: var(--text-main);
    border: none; padding: 10px 20px; border-radius: 8px; font-size: 14px; font-weight: 500; cursor: pointer;
}
.sync-btn.active-auth { background-color: #4caf50; color: white; }

/* Sidebar & Mobile Menu */
.app-body { display: flex; flex: 1; overflow: hidden; position: relative; }
.sidebar { 
    width: 280px; background-color: #ffffff; padding-top: 16px; 
    overflow-y: auto; border-right: 1px solid var(--border-color); 
    transition: transform 0.3s ease;
}
.nav-item {
    display: flex; align-items: center; padding: 0 24px; height: 48px; margin-right: 12px; border-radius: 0 24px 24px 0;
    cursor: pointer; color: var(--text-main); text-decoration: none; transition: background-color 0.2s; gap: 20px;
    font-weight: 500; font-size: 14px;
}
.nav-item i { color: var(--text-light); font-size: 24px; }
.nav-item.active { background-color: var(--primary-light); color: var(--primary-color); }
.nav-item.active i { color: var(--primary-color); }

@media (max-width: 600px) {
    .sidebar { 
        position: absolute; left: 0; top: 0; bottom: 0; z-index: 900;
        box-shadow: 4px 0 8px rgba(0,0,0,0.1);
        transform: translateX(-100%); /* Ẩn sidebar trên mobile mặc định */
    }
    .sidebar.mobile-open {
        transform: translateX(0); /* Hiện sidebar khi bấm menu */
    }
    .app-header { border-bottom: none; box-shadow: 0 2px 4px rgba(0,0,0,0.05); }
    .main-content { padding: 16px; }
}

/* Main Content & Views */
.main-content { flex: 1; padding: 32px 24px; overflow-y: auto; background-color: var(--bg-body); }
.notes-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; align-items: start; }
.note-card {
    background: #ffffff; border: 1px solid var(--border-color); border-radius: 8px; padding: 16px;
    transition: box-shadow 0.2s; cursor: pointer; display: flex; flex-direction: column; gap: 12px;
}
.note-card:hover { box-shadow: 0 1px 3px rgba(0,0,0,0.1); }
.note-card.note-urgent { border-left: 4px solid var(--primary-color); }
.note-title { font-size: 16px; font-weight: 500; }
.note-body { font-size: 14px; color: var(--text-main); line-height: 1.5; display: -webkit-box; -webkit-line-clamp: 6; -webkit-box-orient: vertical; overflow: hidden; }
.note-tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { font-size: 12px; padding: 6px 12px; background-color: rgba(0,0,0,0.05); color: var(--text-light); border-radius: 12px; cursor: pointer;}
.tag:hover { background-color: var(--primary-light); color: var(--primary-dark);}

/* Lịch (Calendar) */
.calendar-container { max-width: 600px; margin: 0 auto; background: #fff; padding: 16px; border-radius: 8px; border: 1px solid var(--border-color); }
.calendar-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.calendar-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 8px; text-align: center; }
.cal-day-name { font-weight: bold; color: var(--text-light); font-size: 14px; margin-bottom: 8px;}
.cal-day { padding: 12px 0; border-radius: 50%; cursor: pointer; font-size: 14px; position: relative; }
.cal-day:hover { background-color: #f0f0f0; }
.cal-day.today { background-color: var(--primary-light); color: var(--primary-dark); font-weight: bold;}
.cal-day.selected { background-color: var(--primary-color); color: white; }
.note-dot { position: absolute; bottom: 2px; left: 50%; transform: translateX(-50%); width: 6px; height: 6px; background-color: red; border-radius: 50%; }

/* Tags View */
.tags-container { display: flex; flex-wrap: wrap; gap: 12px; }
.tags-container .tag { font-size: 16px; padding: 8px 16px; }

/* FAB */
.fab-btn {
    position: fixed; right: 24px; bottom: 24px; width: 56px; height: 56px;
    background-color: var(--fab-color); color: #ffffff;
    border: none; border-radius: 50%; display: flex; align-items: center; justify-content: center;
    cursor: pointer; box-shadow: 0 4px 6px rgba(0,0,0,0.2); z-index: 90;
    transition: transform 0.2s, background-color 0.2s;
}
.fab-btn:hover { background-color: var(--primary-dark); }
.fab-btn:active { transform: scale(1.1); }

/* Editor */
.note-editor-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: #ffffff; display: flex; flex-direction: column;
    z-index: 1001; transform: translateY(100%); transition: transform 0.3s ease-out;
}
.note-editor-overlay.active { transform: translateY(0); }
.editor-header {
    display: flex; align-items: center; justify-content: space-between;
    height: 64px; border-bottom: 1px solid var(--border-color); padding: 0 16px;
}
.editor-header-actions { display: flex; gap: 8px; }
.action-btn:hover { color: var(--editor-active-color); }
.save-btn { color: var(--editor-active-color); }

.color-picker-container { position: relative; }
.color-palette-popup {
    position: absolute; top: 100%; right: 0; background: #ffffff; border: 1px solid var(--border-color);
    border-radius: 8px; padding: 12px; display: none; grid-template-columns: repeat(3, 1fr); gap: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1); z-index: 1002;
}
.color-palette-popup.open { display: grid; }
.color-option { width: 32px; height: 32px; border-radius: 50%; border: 1px solid var(--border-color); cursor: pointer; }
.color-option.active { border: 2px solid var(--editor-active-color); }

.editor-body { flex: 1; padding: 20px; overflow-y: auto; display: flex; flex-direction: column; gap: 16px; transition: background-color 0.3s; }
.editor-title-input { width: 100%; border: none; background: none; outline: none; font-size: 20px; font-weight: 500; color: var(--text-main); font-family: inherit; }
.editor-time-container { display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--text-light); }
.editor-tags-area { padding: 8px 0; display: flex; align-items: center; gap: 12px; border-bottom: 1px solid rgba(0,0,0,0.05); }
.editor-tag-list { display: flex; flex-wrap: wrap; gap: 6px; }
.tag-input { width: 100px; border: none; background: none; outline: none; font-size: 14px; color: var(--editor-active-color); font-family: inherit; }
.editor-textarea { width: 100%; flex: 1; border: none; background: none; outline: none; font-size: 15px; color: var(--text-main); line-height: 1.6; font-family: inherit; resize: none; }

/* Trạng thái Readonly (Chỉ đọc) */
.readonly-mode input, .readonly-mode textarea { pointer-events: none; }