/* --- RESET & GLOBAL STYLES --- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    scroll-behavior: smooth;
}

body {
    background: linear-gradient(#d5eeff, #3498db, #2133f9);
    /* Warna latar belakang yang lembut */
    color: #333;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* --- HEADER & NAVBAR --- */
.heading {
    background-color: #3498db;
    padding: 1.2rem 0;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 999;
}

.navbar {
    display: flex;
    justify-content: space-between;
    /* Memisahkan hamburger/link dengan tombol reload */
    align-items: center;
    padding: 0 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: bold;
    padding: 0.6rem 1.2rem;
    border-radius: 8px;
    background-color: rgba(255, 255, 255, 0.1);
    transition: all 0.3s ease;
}

.nav-links a:hover {
    background-color: #f1c40f;
    color: #2c3e50;
    transform: translateY(-2px);
}

/* Sembunyikan tombol hamburger di layar PC */
.hamburger {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 2rem;
    cursor: pointer;
    box-shadow: none;
    padding: 0;
    margin: 0;
}

.hamburger:active {
    transform: scale(0.9);
}

/* --- TAMPILAN MOBILE (HP) --- */
@media screen and (max-width: 768px) {

    /* Tampilkan ikon hamburger */
    .hamburger {
        display: block;
    }

    /* Sembunyikan menu link secara default dan buat menurun */
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        /* Turun tepat di bawah header */
        left: 0;
        width: 100%;
        background-color: #34495e;
        padding: 1rem 0;
        gap: 0.5rem;
        z-index: 10;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    }

    /* Kelas untuk memunculkan menu via JavaScript */
    .nav-links.aktif {
        display: flex;
    }

    .nav-links a {
        text-align: center;
        margin: 0 2rem;
        /* Jarak agar tidak terlalu mepet layar */
    }
}

/* --- MAIN LAYOUT (GRID) --- */
.main {
    flex: 1;
    display: grid;
    /* Membuat grid responsif: 2 kolom di PC, 1 kolom di HP */
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    padding: 2.5rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

/* --- KOTAK MESIN PERHITUNGAN --- */
[id^="container-"] {
    background-color: #ecf0f1;
    border: 3px solid #bdc3c7;
    border-radius: 20px;
    padding: 2rem 1.5rem;
    /* Memberikan efek 3D pada mesin */
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.15), inset 0 5px 0 rgba(255, 255, 255, 0.8);
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
}

/* Label Mesin (Judul di atas mesin) */
[id^="container-"]>label {
    font-size: 1.2rem;
    font-weight: 800;
    color: white;
    padding: 0.6rem 2rem;
    border-radius: 30px;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    text-transform: uppercase;
    letter-spacing: 2px;
    position: absolute;
    top: -20px;
    /* Membuat label sedikit keluar dari kotak */
}

/* Warna berbeda untuk setiap operasi */
#container-perkalian>label {
    background-color: #e74c3c;
}

/* Merah */
#container-pembagian>label {
    background-color: #9b59b6;
}

/* Ungu */
#container-penambahan>label {
    background-color: #27ae60;
}

/* Hijau */
#container-pengurangan>label {
    background-color: #e67e22;
}

/* Oranye */

/* Layar Soal (Seperti layar LCD) */
.soal-kali,
.soal-bagi,
.soal-tambah,
.soal-kurang {
    background-color: #d1ecf1;
    border: 4px solid #7f8c8d;
    border-radius: 12px;
    padding: 2rem 1rem;
    width: 100%;
    text-align: center;
    box-shadow: inset 0 4px 8px rgba(0, 0, 0, 0.2);
    margin-top: 10px;
}

/* Teks Angka & Operator */
.soal-kali span,
.soal-bagi span,
.soal-tambah span,
.soal-kurang span {
    font-family: 'Courier New', Courier, monospace;
    /* Font ala mesin */
    font-size: 2.5rem;
    font-weight: bold;
    color: #2c3e50;
    margin: 0 5px;
    vertical-align: middle;
}

/* Input Jawaban */
input[type="text"] {
    width: 100px;
    padding: 10px;
    font-size: 1.5rem;
    text-align: center;
    font-weight: bold;
    border: 3px solid #bdc3c7;
    border-radius: 10px;
    margin: 20px auto;
    display: block;
    outline: none;
    transition: border-color 0.3s;
}

input[type="text"]:focus {
    border-color: #3498db;
    box-shadow: 0 0 8px rgba(52, 152, 219, 0.4);
}

/* Tombol Aksi */
button {
    padding: 12px 25px;
    font-size: 1.1rem;
    font-weight: bold;
    color: #000000;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    margin: 5px;
    transition: transform 0.1s, box-shadow 0.1s;
    /* Efek tombol 3D yang bisa ditekan */
    box-shadow: 0 6px 0 rgba(0, 0, 0, 0.2);
}

button:active {
    transform: translateY(6px);
    box-shadow: none;
}

/* Warna Tombol spesifik (berdasarkan urutan di HTML) */
button:nth-of-type(1) {
    background-color: transparent;
}

/* Tombol Jawab (Biru) */
button:nth-of-type(2) {
    background-color: transparent;
}

/* Tombol Lanjut (Abu-abu) */

/* Teks Status */
#status,
#jawaban-komputer {
    margin-top: 15px;
    font-size: 1.1rem;
    font-weight: bold;
    min-height: 25px;
}

/* --- FOOTER --- */
.footer {
    background-color: #2c3e50;
    color: #ecf0f1;
    padding: 2.5rem 1rem 1rem 1rem;
}

.footer-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
    align-items: center;
    margin-bottom: 2rem;
    max-width: 1000px;
    margin: 0 auto 2rem auto;
}

.footer-info h3 {
    color: #f1c40f;
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #3498db;
    text-decoration: none;
    margin: 0 15px;
    transition: color 0.3s;
}

.footer-links a:hover {
    color: #f1c40f;
}

.footer-bottom {
    text-align: center;
    border-top: 1px solid #34495e;
    padding-top: 1.5rem;
    font-size: 0.9rem;
}