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

body {
    font-family: Arial, sans-serif;
    background-color: #101927;
    color: #e2e8f0;
    transition: 0.3s;
    overflow: hidden;
}

.landing-page {
    position: fixed;
    inset: 0;
    background: linear-gradient(135deg, #192e4f, #121b2c);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
    text-align: center;
}

.landing-card {
    width: 100%;
    max-width: 520px;
    background: rgba(18, 29, 44, 0.96);
    border-radius: 24px;
    padding: 40px 30px;
    box-shadow: 0 30px 80px rgba(0, 0, 0, 0.35);
}

.landing-card h1 {
    margin-bottom: 18px;
    color: #dce7ff;
    font-size: clamp(2rem, 3vw, 2.8rem);
}

.landing-card p {
    margin-bottom: 28px;
    color: #b8c7e3;
    line-height: 1.6;
    font-size: 1rem;
}

.enter-btn {
    padding: 14px 30px;
    border: none;
    border-radius: 999px;
    background: #1d4d7a;
    color: white;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s ease, transform 0.2s ease;
}

.enter-btn:hover {
    background: #153a60;
    transform: translateY(-1px);
}

/* --- DARK MODE --- */
body.dark-mode {
    background-color: #0b1219 !important;
    color: #e2e8f0 !important;
}
body.dark-mode .box {
    background-color: #17202c !important;
    color: #e2e8f0 !important;
    box-shadow: 8px 8px 0px #1d4d7a;
}
body.dark-mode header,
body.dark-mode .sidemenu {
    background-color: #0f1722 !important;
}

header {
    background: #1f2f48;
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 24px;
    gap: 20px;
    min-height: 80px;
}

.brand {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.brand h1 {
    margin: 0;
    font-size: 1.6rem;
}

.brand-subtitle {
    margin: 0;
    font-size: 0.95rem;
    color: #a8b7d3;
}

.container {
    display: grid;
    grid-template-columns: 1.85fr 1fr;
    gap: 24px;
    height: calc(100vh - 112px);
    padding: 24px;
}

.sidemenu {
    background-color: #162135;
    padding: 24px;
    display: block;
    overflow-y: auto;
    border-left: 2px solid #0d1a2d;
    border-radius: 24px 24px 24px 24px;
    box-shadow: inset 0 0 0 1px rgba(255,255,255,0.04);
}

.content {
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    overflow: hidden;
}

.toggle-btn {
    width: auto;
    padding: 12px 18px;
    max-width: 160px;
}

.box {
    background: #162538;
    padding: 40px;
    border-radius: 16px;
    box-shadow: 10px 10px 0px #1d4d7a;
    width: 100%;
    max-width: 1000px;
    overflow-y: auto;
    max-height: calc(100vh - 140px);
}

/* Vintage Scrollbar Styling */
.box::-webkit-scrollbar {
    width: 10px;
}

.box::-webkit-scrollbar-track {
    background: #0f1722;
    border-radius: 5px;
}

.box::-webkit-scrollbar-thumb {
    background: #1d4d7a;
    border-radius: 5px;
}

.box::-webkit-scrollbar-thumb:hover {
    background: #153a60;
}

.menu-btn,
.vintage-btn,
.toggle-btn {
    width: 100%;
    padding: 12px;
    margin: 5px 0;
    background: #1d4d7a;
    color: white;
    border: none;
    cursor: pointer;
    font-weight: bold;
    border-radius: 8px;
}

.act-btn {
    width: 90%;
    margin-left: 10%;
    padding: 10px;
    margin-top: 4px;
    background: #203a63;
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    text-align: left;
}

.menu-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    color: #a8b7d3;
    margin-top: 10px;
}

.divider {
    border: 0;
    height: 1px;
    background: #2e4b72;
    margin: 15px 0;
}

input {
    width: 100%;
    padding: 12px;
    margin: 10px 0;
    border: 2px solid #1d4d7a;
    border-radius: 8px;
    background: #122138;
    color: #e2e8f0;
}

@media (max-width: 768px) {
    .container {
        display: flex;
        flex-direction: column;
        height: auto;
        padding: 16px;
    }
    .content,
    .sidemenu {
        width: 100%;
        height: auto;
    }
    .sidemenu {
        display: none;
        border-left: none;
        border-right: none;
    }
    header {
        flex-wrap: wrap;
        padding: 16px;
    }
    .toggle-btn {
        width: 100%;
    }
}

/* --- EXERCISE 4 STYLES (VINTAGE THEME) --- */
.input-section {
    background: #172635;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    border: 2px solid #1d4d7a;
    box-shadow: 4px 4px 0px #0f1722;
}

.input-section h4 {
    color: #e2e8f0;
    margin-bottom: 15px;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.num-items-section {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.num-items-section .input-group {
    flex: 1;
    min-width: 200px;
}

.quiz-item,
.exam-item {
    background: #1f3250;
    padding: 15px;
    border-radius: 6px;
    margin-bottom: 15px;
    border: 2px solid #122138;
}

/* quiz & exam score inputs (score out of 50) */
.quiz-score,
.exam-score {
    width: 100%;
    padding: 12px;
    border: 2px solid #122138;
    border-radius: 4px;
    background: #1f2f45;
    color: #e2e8f0;
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.quiz-score:focus,
.exam-score:focus {
    border-color: #5d4037;
    outline: none;
    box-shadow: 0 0 0 2px #8d6e63;
}

.secondary-btn {
    background: #5d4037;
    color: white;
    border: none;
    padding: 12px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    margin-top: 10px;
    transition: background 0.2s;
    font-weight: bold;
    text-transform: uppercase;
}

.secondary-btn:hover {
    background: #4e342e;
}

.secondary-btn:active {
    transform: scale(0.98);
}

.input-group {
    margin-bottom: 15px;
    text-align: left;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 0.9rem;
    color: #efebe9; /* White text */
    font-weight: bold;
}

.input-group input {
    width: 100%;
    padding: 12px;
    border: 2px solid #5d4037;
    border-radius: 4px;
    background: #d7ccc8;
    color: #2b1b17; /* Dark text on light background */
    font-size: 0.9rem;
}

.input-group input:focus {
    border-color: #8d6e63;
    outline: none;
    box-shadow: 0 0 0 2px #5d4037;
}

.button-group {
    display: flex;
    gap: 15px;
    margin-top: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.grade-badge {
    display: inline-block;
    padding: 8px 20px;
    background: #5d4037;
    color: white;
    border-radius: 4px;
    font-weight: bold;
    font-size: 1.2rem;
    border: 2px solid #3e2723;
}

.output-display {
    margin-top: 25px;
    padding: 20px;
    background: #3e2723;
    border-radius: 8px;
    text-align: left;
    border: 2px solid #5d4037;
    box-shadow: 4px 4px 0px #2b1b17;
}

.output-display p {
    padding: 10px;
    margin: 8px 0;
    background: #5d4037;
    border-left: 4px solid #8d6e63;
    border-radius: 4px;
    font-size: 0.9rem;
    color: #efebe9; /* White text */
}

.output-display .error {
    border-left-color: #8d6e63;
    color: #efebe9;
}

.output-display .success {
    border-left-color: #8d6e63;
    color: #efebe9;
}

.output-display hr {
    border: 1px solid #5d4037;
    margin: 15px 0;
}

/* Grade Badge Colors */
.grade-badge.A {
    background: #8d6e63;
}

.grade-badge.B {
    background: #5d4037;
}

.grade-badge.C {
    background: #8d6e63;
}

.grade-badge.D {
    background: #5d4037;
}

.grade-badge.F {
    background: #3e2723;
}

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

.output-display {
    animation: fadeIn 0.3s ease forwards;
}

/* Hover Effects */
.quiz-item:hover,
.exam-item:hover {
    background: #4e342e;
    border-color: #5d4037;
}

/* Focus States */
input:focus {
    box-shadow: 0 0 0 2px rgba(141, 110, 99, 0.3);
}

/* Disabled State */
input:disabled {
    background: #5d4037;
    cursor: not-allowed;
}