:root {
    /* Color Palette - Premium White & Gray Base */
    --bg-primary: #F8F9FA;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #F1F3F5;
    
    --text-primary: #212529;
    --text-secondary: #495057;
    --text-tertiary: #868E96;
    
    --border-light: rgba(0, 0, 0, 0.05);
    --border-strong: rgba(0, 0, 0, 0.1);
    
    --accent: #212529;
    --accent-hover: #343A40;
    --accent-light: rgba(33, 37, 41, 0.05);
    
    /* Semantic Colors */
    --success: #37B24D;
    --success-light: rgba(55, 178, 77, 0.1);
    --warning: #F59F00;
    --warning-light: rgba(245, 159, 0, 0.1);
    --danger: #F03E3E;
    --danger-light: rgba(240, 62, 62, 0.1);
    --info: #1C7ED6;
    --info-light: rgba(28, 126, 214, 0.1);
    
    /* Variables */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --sidebar-width: 280px;
    --header-height: 80px;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 24px 48px rgba(0, 0, 0, 0.08);
    
    /* Transitions */
    --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Plus Jakarta Sans', 'Noto Sans JP', sans-serif;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    -webkit-font-smoothing: antialiased;
    overflow: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    letter-spacing: -0.02em;
}

/* Views */
.view {
    display: none;
    opacity: 0;
    transition: opacity var(--transition-base);
    height: 100vh;
    width: 100vw;
}

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

/* --- Login View --- */
.login-split {
    display: flex;
    width: 100%;
}

.login-left {
    flex: 1;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    position: relative;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
}

.graphic-shape {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
    filter: blur(40px);
}

.shape1 { width: 500px; height: 500px; top: -100px; left: -100px; }
.shape2 { width: 400px; height: 400px; bottom: -50px; right: -50px; }

.login-right {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
}

.login-card {
    width: 100%;
    max-width: 420px;
    padding: 40px;
}

.login-header {
    margin-bottom: 40px;
}

.logo {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.05em;
    margin-bottom: 24px;
    background: linear-gradient(135deg, #212529, #495057);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.login-header h2 { font-size: 1.75rem; margin-bottom: 8px; }
.login-header p { color: var(--text-secondary); font-size: 0.95rem; }

.input-group {
    margin-bottom: 24px;
}

.input-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-secondary);
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-wrapper i {
    position: absolute;
    left: 16px;
    color: var(--text-tertiary);
    font-size: 1.25rem;
}

input[type="email"],
input[type="password"],
input[type="text"],
input[type="number"],
input[type="date"] {
    width: 100%;
    padding: 14px 16px 14px 44px; /* Space for icon */
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-md);
    font-size: 1rem;
    background: var(--bg-primary);
    transition: var(--transition-fast);
    outline: none;
}

input:focus {
    border-color: var(--text-primary);
    background: var(--bg-secondary);
    box-shadow: 0 0 0 3px var(--accent-light);
}

select {
   width: 100%;
   padding: 14px 16px;
   border: 1px solid var(--border-strong);
   border-radius: var(--radius-md);
   font-size: 1rem;
   outline: none;
   background: var(--bg-primary);
}

textarea {
   width: 100%;
   padding: 14px 16px;
   border: 1px solid var(--border-strong);
   border-radius: var(--radius-md);
   font-size: 1rem;
   outline: none;
   resize: vertical;
}

.btn-primary {
    background: var(--accent);
    color: white;
    border: none;
    padding: 16px 24px;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    margin-top: 16px;
}

.btn-primary:hover { background: var(--accent-hover); transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-block { width: 100%; }

.error-msg {
    color: var(--danger);
    font-size: 0.875rem;
    margin-top: 8px;
    min-height: 20px;
}

/* --- App View --- */
#app-view {
    display: flex;
    background: var(--bg-primary);
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-light);
    display: flex;
    flex-direction: column;
    z-index: 10;
}

.sidebar-header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    padding: 0 32px;
}

.sidebar-header .logo { margin: 0; font-size: 1.5rem; }

.sidebar-nav {
    flex: 1;
    padding: 24px 16px;
    overflow-y: auto;
}

.sidebar-nav ul { list-style: none; }

.sidebar-nav li {
    display: flex;
    align-items: center;
    padding: 14px 16px;
    margin-bottom: 8px;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition-fast);
    font-weight: 500;
}

.sidebar-nav li i { font-size: 1.25rem; margin-right: 12px; }
.sidebar-nav li:hover { background: var(--bg-tertiary); color: var(--text-primary); }
.sidebar-nav li.active { background: var(--accent); color: white; }
.sidebar-nav li.active i { color: white; }

.sidebar-footer {
    padding: 24px;
    border-top: 1px solid var(--border-light);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
}

.avatar {
    width: 40px; height: 40px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex; align-items: center; justify-content: center;
    color: var(--text-secondary);
}

.user-info { display: flex; flex-direction: column; }
.user-info span { font-size: 0.875rem; font-weight: 600; }
.user-info .sub-text { font-size: 0.75rem; color: var(--text-tertiary); font-weight: 400; }

.btn-icon {
    background: none; border: none; font-size: 1.25rem;
    color: var(--text-secondary); cursor: pointer;
    padding: 8px; border-radius: var(--radius-sm); transition: var(--transition-fast);
}
.btn-icon:hover { background: var(--bg-tertiary); color: var(--danger); }

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.topbar {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 40px;
    background: rgba(248, 249, 250, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-light);
    z-index: 5;
}

.topbar h2 { font-size: 1.25rem; font-weight: 600; }

.topbar-actions { display: flex; align-items: center; gap: 16px; }
.date-display { font-size: 0.875rem; color: var(--text-secondary); font-weight: 500;}

.page-container {
    flex: 1;
    padding: 40px;
    overflow-y: auto;
}

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

.fade-in { animation: fadeIn 0.4s ease forwards; }

/* --- Responsive & Mobile Support --- */
.mobile-only { display: none; }

@media (max-width: 768px) {
    .mobile-only { display: flex; }
    
    /* Login */
    .login-split { flex-direction: column; height: 100vh; }
    .login-left { display: none; } /* Hide decoration on small screens */
    .login-card { padding: 24px; }
    
    /* Sidebar as Off-Canvas */
    .sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        bottom: 0;
        z-index: 100;
        box-shadow: var(--shadow-lg);
        transition: left 0.3s ease;
    }
    .sidebar.open {
        left: 0;
    }
    .sidebar-overlay {
        display: none;
        position: fixed;
        top: 0; left: 0; right: 0; bottom: 0;
        background: rgba(0,0,0,0.4);
        z-index: 90;
    }
    .sidebar-overlay.active { display: block; }
    
    /* Topbar & Header */
    .topbar { padding: 0 16px; flex-wrap: wrap; }
    .page-container { padding: 16px; }
    
    #current-date { display: none; } /* Hide date on very tight screens */
    
    /* Grid adjustments */
    .grid { grid-template-columns: 1fr; gap: 16px; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    
    /* Table Responsive Wrapper */
    .table-container {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        border: 1px solid var(--border-light);
        border-radius: var(--radius-sm);
        margin-bottom: 16px;
    }
    table { width: 100%; min-width: 600px; } /* Ensures the table doesn't squish unreadably */
    
    /* Modal sizing */
    .modal-content { width: 95%; max-width: 95%; padding: 24px 16px; margin: 20px auto; }
    
    /* Tabs wrap */
    .tabs { flex-wrap: wrap; }
    .tab { flex: 1 1 calc(50% - 16px); text-align: center; }
}