:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --bg-light: #f8fafc;
    --card-bg: rgba(255, 255, 255, 0.8);
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --glass-border: rgba(255, 255, 255, 0.3);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

[data-theme="dark"] {
    --bg-light: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --border: #334155;
    --glass-border: rgba(255, 255, 255, 0.1);
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-main);
    line-height: 1.5;
    transition: background-color 0.3s ease, color 0.3s ease;
    margin: 0;
    min-height: 100vh;
}

.glass-card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 1rem;
    box-shadow: var(--shadow);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 1rem;
    position: relative; /* For absolutely positioned theme toggle */
}

header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.8s ease-out;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #4f46e5 0%, #06b6d4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.status-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.status-active { background: var(--clr-active); color: white; box-shadow: 0 2px 8px rgba(16, 185, 129, 0.2); }
.status-upcoming { background: var(--clr-upcoming); color: white; box-shadow: 0 2px 8px rgba(79, 70, 229, 0.2); }
.status-future { background: rgba(79, 70, 229, 0.25); color: var(--clr-upcoming); border: 1.5px solid var(--clr-upcoming); }
.status-ended { background: var(--clr-ended); color: white; opacity: 0.8; }

.card-future { opacity: 0.9; }
.card-ended { opacity: 0.7; }

/* Tabs */
.nav-tabs {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.nav-link {
    padding: 0.75rem 1.5rem;
    border-radius: 0.75rem;
    border: 1px solid var(--border);
    background: var(--card-bg);
    color: var(--text-main);
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s ease;
    text-decoration: none;
}

.nav-link.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
    box-shadow: 0 10px 15px -3px rgba(79, 70, 229, 0.4);
}

/* Specific Semester Theme Coloring */
[data-semester-theme="2"] { --semester-accent: #10b981; --semester-glow: rgba(16, 185, 129, 0.4); }
[data-semester-theme="4"] { --semester-accent: #f59e0b; --semester-glow: rgba(245, 158, 11, 0.4); }
[data-semester-theme="6"] { --semester-accent: #6366f1; --semester-glow: rgba(99, 102, 241, 0.4); }
[data-semester-theme="1"] { --semester-accent: #ec4899; --semester-glow: rgba(236, 72, 153, 0.4); }
[data-semester-theme="3"] { --semester-accent: #8b5cf6; --semester-glow: rgba(139, 92, 246, 0.4); }
[data-semester-theme="5"] { --semester-accent: #06b6d4; --semester-glow: rgba(6, 182, 212, 0.4); }

/* Global variables for Dynamic Buttons */
:root {
    --semester-accent: #4f46e5;
    --semester-glow: rgba(79, 70, 229, 0.4);
}

.nav-link[data-semester="2"].active, [data-semester-theme="2"] .nav-link.active {
    background: #10b981;
    border-color: #10b981;
    color: white;
    box-shadow: 0 10px 15px -3px rgba(16, 185, 129, 0.4);
}

.nav-link[data-semester="4"].active, [data-semester-theme="4"] .nav-link.active {
    background: #f59e0b;
    border-color: #f59e0b;
    color: white;
    box-shadow: 0 10px 15px -3px rgba(245, 158, 11, 0.4);
}

.nav-link[data-semester="6"].active, [data-semester-theme="6"] .nav-link.active {
    background: #6366f1;
    border-color: #6366f1;
    color: white;
    box-shadow: 0 10px 15px -3px rgba(99, 102, 241, 0.4);
}

.nav-link:not(.active):hover {
    transform: translateY(-2px);
    border-color: var(--text-muted);
}

/* Search Bar */
.search-container {
    position: relative;
    max-width: 600px;
    margin: 0 auto 0.4rem auto;
}

.search-input {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    background: var(--card-bg);
    color: var(--text-main);
    font-size: 1rem;
    transition: all 0.2s ease;
}

.search-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

.search-icon {
    position: absolute;
    left: 1.2rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--primary);
    font-size: 1.1rem;
    transition: all 0.3s ease;
    pointer-events: none;
}

.search-input:focus + .search-icon {
    transform: translateY(-50%) scale(1.1);
    color: var(--primary-hover);
}

/* Info Bar */
#infoHariTanggal {
    text-align: center;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 2rem;
    color: var(--text-muted);
    letter-spacing: 0.5px;
}

#infoHariTanggal i {
    color: var(--primary);
    margin-right: 0.3rem;
}

#noData {
    display: none;
    padding: 3rem;
    text-align: center;
    color: var(--text-muted);
}

#noData i {
    font-size: 2.5rem;
    display: block;
    margin-bottom: 1rem;
    opacity: 0.5;
}

#noData p {
    font-size: 0.95rem;
}

.refresh-status {
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 1.5rem;
    font-style: italic;
    opacity: 0.7;
}

footer {
    text-align: center;
    margin-top: 4rem;
    color: var(--text-muted);
    font-size: 0.75rem;
    border-top: 1px solid var(--border);
    padding: 2rem 1rem;
    letter-spacing: 0.3px;
    line-height: 1.6;
}

/* --- Skeleton Loading --- */
@keyframes shimmer {
    0%   { background-position: -800px 0; }
    100% { background-position: 800px 0; }
}

.skeleton-wrapper {
    padding: 1rem;
}

.skeleton-row {
    display: flex;
    gap: 1rem;
    align-items: center;
    padding: 1rem;
    margin-bottom: 0.6rem;
    border-radius: 0.75rem;
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-left: 4px solid var(--semester-accent);
    opacity: 0.8;
}

.skeleton-block {
    border-radius: 6px;
    background: linear-gradient(90deg, var(--border) 25%, rgba(255,255,255,0.3) 50%, var(--border) 75%);
    background-size: 800px 100%;
    animation: shimmer 1.5s infinite linear;
    flex-shrink: 0;
}

.skeleton-block.sm  { height: 12px; width: 80px; }
.skeleton-block.md  { height: 14px; width: 140px; }
.skeleton-block.lg  { height: 16px; width: 220px; }
.skeleton-block.btn { height: 32px; width: 90px; border-radius: 8px; margin-left: auto; }

/* Mobile skeleton card */
.skeleton-card {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-left: 4px solid var(--semester-accent);
    border-radius: 12px;
    padding: 1.25rem;
    margin-bottom: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.85rem;
}

/* --- CSS-Only Tooltip for Locked Button --- */
.tooltip-wrapper {
    position: relative;
    display: block;
    width: 100%;
}

.tooltip-wrapper::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) scale(0.9);
    background: #1e293b;
    color: #f8fafc;
    font-size: 11px;
    font-weight: 500;
    padding: 0.4rem 0.75rem;
    border-radius: 6px;
    white-space: nowrap;
    pointer-events: none;
    opacity: 0;
    transition: all 0.2s ease;
    z-index: 50;
    letter-spacing: 0.3px;
}

.tooltip-wrapper::before {
    content: '';
    position: absolute;
    bottom: calc(100% + 2px);
    left: 50%;
    transform: translateX(-50%) scale(0.9);
    border: 5px solid transparent;
    border-top-color: #1e293b;
    pointer-events: none;
    opacity: 0;
    transition: all 0.2s ease;
    z-index: 50;
}

.tooltip-wrapper:hover::after,
.tooltip-wrapper:hover::before {
    opacity: 1;
    transform: translateX(-50%) scale(1);
}

[data-theme="dark"] .tooltip-wrapper::after {
    background: #f8fafc;
    color: #1e293b;
}

[data-theme="dark"] .tooltip-wrapper::before {
    border-top-color: #f8fafc;
}

/* --- Senior UI/UX Refinement & Global Reset --- */
*, *::before, *::after {
    box-sizing: border-box;
}

:root {
    --fz-body: 14px;
    --fz-micro: 11px;
    
    /* Default Branding */
    --semester-accent: #4f46e5;
    --semester-glow: rgba(79, 70, 229, 0.4);
    
    /* Semantic Colors */
    --clr-active: #10b981;  /* Emerald */
    --clr-upcoming: #4f46e5; /* Indigo */
    --clr-ended: #64748b;    /* Slate */
}

/* --- Dynamic Semester Branding Themes --- */
[data-semester-theme="2"] {
    --semester-accent: #10b981;
    --semester-glow: rgba(16, 185, 129, 0.4);
    --primary: #10b981;
}

[data-semester-theme="4"] {
    --semester-accent: #f59e0b;
    --semester-glow: rgba(245, 158, 11, 0.4);
    --primary: #f59e0b;
}

[data-semester-theme="6"] {
    --semester-accent: #6366f1;
    --semester-glow: rgba(99, 102, 241, 0.4);
    --primary: #6366f1;
}

/* --- Desktop: Compact Professional Table --- */
.table-container {
    padding: 1rem;
}

#desktopTable {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0 0.6rem;
}

#desktopTable th {
    padding: 1rem;
    font-size: var(--fz-small);
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    border-bottom: 2px solid var(--semester-accent);
    text-align: left;
    transition: border-color 0.3s ease;
}

.table-row-premium {
    background: var(--card-bg);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: default;
}

.table-row-premium:hover {
    transform: translateY(-3px);
    background: var(--card-bg);
    box-shadow: 0 12px 20px -10px var(--semester-glow);
    z-index: 10;
    position: relative;
}

.table-row-premium td {
    padding: 1rem;
    font-size: var(--fz-body);
    vertical-align: middle;
    border-top: 1px solid var(--glass-border);
    border-bottom: 1px solid var(--glass-border);
}

/* Mixed Alignment for Balance */
#desktopTable th:nth-child(2), #desktopTable td:nth-child(2),
#desktopTable th:nth-child(5), #desktopTable td:nth-child(5) {
    text-align: center;
}

.table-row-premium td:first-child { 
    border-left: 4px solid var(--semester-accent); 
    border-radius: 0.75rem 0 0 0.75rem; 
    transition: border-color 0.3s ease;
}

/* Strip color follows Semester Theme for Unity */
.table-row-premium.row-active td:first-child { border-left-color: var(--semester-accent); }
.table-row-premium.row-ended td:first-child { border-left-color: var(--semester-accent); opacity: 0.6; }

.table-row-premium td:last-child { 
    border-right: 1px solid var(--glass-border); 
    border-radius: 0 0.75rem 0.75rem 0; 
}

/* --- Mobile: Senior Card System --- */
#mobileCardList {
    padding: 1rem 0.75rem;
}

.exam-card {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-left: 4px solid var(--semester-accent); /* Branded Strip */
    border-radius: 12px;
    padding: 1.25rem;
    margin-bottom: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.85rem;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
    position: relative;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.exam-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px var(--semester-glow);
}

/* Card Status Variants (Strip stays Branded) */
.card-active {  }
.card-ended { opacity: 0.7; }

.card-title {
    font-size: var(--fz-title);
    font-weight: 700;
    color: var(--text-main);
    line-height: 1.4;
    word-break: break-word;
}

.card-meta-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.time-header {
    font-size: 13px;
    font-weight: 700;
    color: var(--semester-accent);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: color 0.3s ease;
}

.sesi-label {
    font-size: var(--fz-micro);
    background: rgba(0,0,0,0.05);
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    color: var(--text-muted);
}

.kelas-badge {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.5);
    border: 1px solid var(--semester-accent);
    color: var(--semester-accent);
    transition: all 0.3s ease;
    white-space: nowrap;
}

[data-theme="dark"] .kelas-badge {
    background: rgba(255, 255, 255, 0.05);
}

.card-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    margin-top: 0.25rem;
}

.grid-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 12px;
    color: var(--text-muted);
}

.grid-item i { color: var(--clr-upcoming); opacity: 0.7; }

/* Sentence Case Refresh */
.btn-premium {
    display: block;
    width: 100%;
    padding: 0.85rem;
    border-radius: 10px;
    text-align: center;
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
}

.btn-active {
    background: var(--clr-active);
    color: white;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

.btn-upcoming {
    background: transparent;
    border: 1.5px solid var(--clr-upcoming);
    color: var(--clr-upcoming);
}

.btn-ended {
    background: #f1f5f9;
    color: #94a3b8;
    cursor: not-allowed;
}

[data-theme="dark"] .btn-ended {
    background: #1e293b;
    color: #475569;
}

/* Header & Tab refinement */
.header-main {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    margin-bottom: 2.5rem;
    gap: 1.5rem;
}

.header-brand {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.header-brand img {
    width: 100px;
    height: auto;
    filter: drop-shadow(0 4px 12px rgba(0,0,0,0.1));
}

.header-text h1 {
    margin: 0 0 0.5rem 0;
    font-size: 2.2rem;
    letter-spacing: -0.025em;
}

.header-text p {
    margin: 0;
    color: var(--text-muted);
    font-size: 1rem;
}

#themeToggle {
    position: absolute;
    top: 1rem;
    right: 1rem;
    width: 2.8rem;
    height: 2.8rem;
    border-radius: 50%;
    background: var(--card-bg);
    border: 1px solid var(--border);
    color: var(--text-main);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
    z-index: 100;
}

#themeToggle:hover {
    background: var(--semester-glow);
    border-color: var(--semester-accent);
}

.date-separator {
    text-align: center;
    padding: 2rem 0 1rem 0;
    font-weight: 700;
    font-size: 13px;
    color: var(--text-muted);
    text-transform: capitalize; /* Better than uppercase */
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.date-separator::before, .date-separator::after {
    content: ""; flex: 1; height: 1px; background: var(--border);
}

/* --- Hard Switch: Truly Distinct Desktop vs Mobile Layouts --- */
@media (min-width: 769px) {
    .table-container { 
        display: block !important; 
    }
    #mobileCardList { 
        display: none !important; 
    }
}

@media (max-width: 768px) {
    #desktopContainer, .table-container, #desktopTable, thead, th { 
        display: none !important; 
        visibility: hidden !important;
        opacity: 0 !important;
        height: 0 !important;
        pointer-events: none !important;
    }
    #mobileCardList { 
        display: block !important; 
        visibility: visible !important;
        opacity: 1 !important;
        height: auto !important;
        padding: 0.5rem 0.25rem;
    }
    .container { padding: 0.5rem 0.75rem; }
    
    .header-main { margin-bottom: 1rem; gap: 0.5rem; }
    .header-brand img { width: 70px !important; }
    .header-text h1 { font-size: 1.3rem !important; margin-bottom: 0.1rem !important; }
    .header-text p { display: block; font-size: 0.75rem; opacity: 0.9; } 
    
    .nav-tabs { gap: 0.25rem; margin-bottom: 0.75rem; }
    .nav-link { padding: 0.4rem 0.75rem; font-size: 0.75rem; border-radius: 0.5rem; }
    
    .search-container { margin-bottom: 0.5rem; }
    .search-input { padding: 0.6rem 0.6rem 0.6rem 2.5rem; font-size: 0.8rem; border-radius: 0.75rem; }

    /* Compact Cards */
    .exam-card { 
        padding: 0.85rem; 
        margin-bottom: 0.75rem; 
        gap: 0.5rem; 
        border-radius: 10px;
    }
    .card-title { font-size: 0.95rem; }
    .time-header { font-size: 11px; }
    .grid-item { font-size: 11px; gap: 0.35rem; }
    .card-grid { gap: 0.5rem; }
    .btn-premium { padding: 0.6rem; font-size: 12px; }
}

    .btn-premium { padding: 0.6rem; font-size: 12px; }
}

/* --- Scroll to Top Button (Premium Glass) --- */
.premium-back-to-top {
    position: fixed;
    bottom: 4rem;
    right: 2rem !important;
    left: auto !important;
    width: 3.8rem;
    height: 3.8rem;
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.9) 0%, rgba(6, 182, 212, 0.9) 100%);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    cursor: pointer;
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 15px 35px rgba(79, 70, 229, 0.5), inset 0 0 15px rgba(255, 255, 255, 0.2);
    opacity: 0;
    visibility: hidden;
    transform: translateY(30px);
    transition: all 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 9999;
}

.premium-back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.premium-back-to-top:hover {
    background: linear-gradient(135deg, rgba(79, 70, 229, 1) 0%, rgba(6, 182, 212, 1) 100%);
    transform: scale(1.1) translateY(-5px);
    color: white;
    box-shadow: 0 20px 45px rgba(79, 70, 229, 0.6);
}

.premium-back-to-top i {
    animation: floatIcon 2s ease-in-out infinite;
}

@keyframes floatIcon {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-3px); }
}

@media (max-width: 768px) {
    .premium-back-to-top {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 3rem;
        height: 3rem;
        font-size: 1.1rem;
    }
}

/* Utility Bar Above Tabs */
.top-utility-bar {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 0.75rem;
}

#infoHariTanggal {
    margin-bottom: 0;
}

/* --- Utility Buttons (Hari Ini & Semua Hari) --- */
.utility-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-eval {
    background: var(--card-bg);
    border: 1px solid var(--semester-accent);
    color: var(--semester-accent);
    padding: 0.5rem 1.25rem;
    border-radius: 999px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-eval:hover {
    background: var(--semester-accent);
    color: white;
    box-shadow: 0 4px 12px var(--semester-glow);
}

.btn-eval.active {
    background: var(--semester-accent);
    color: white;
    box-shadow: 0 0 15px var(--semester-glow);
}

@media (max-width: 768px) {
    .utility-actions {
        width: auto !important;
        gap: 0.5rem;
    }
    .btn-eval {
        flex: none !important;
        width: auto !important;
        display: inline-flex !important;
        justify-content: center;
        font-size: 0.75rem;
        padding: 0.5rem 1rem;
    }
}