/* =====================================
   Visualised™
   Fractions Stylesheet
   Part 1/3
===================================== */

/* ===========================
   Root Variables
=========================== */

:root{

    --bg:#0f172a;
    --surface:#1e293b;
    --surface-hover:#263548;

    --primary:#4f46e5;
    --primary-hover:#6366f1;

    --text:#f8fafc;
    --muted:#94a3b8;

    --border:rgba(255,255,255,.08);

    --radius:22px;

    --shadow:
        0 20px 50px rgba(0,0,0,.45);

    --transition:.3s ease;

}

/* ===========================
   Reset
=========================== */

*{

    margin:0;
    padding:0;
    box-sizing:border-box;

}

html{

    scroll-behavior:smooth;

}

body{

    font-family:"Inter",sans-serif;

    background:var(--bg);

    color:var(--text);

    overflow-x:hidden;

    min-height:100vh;

    line-height:1.7;

    position:relative;

}

/* ===========================
   Animated Grid
=========================== */

body::before{

    content:"";

    position:fixed;

    inset:0;

    background:

        linear-gradient(rgba(255,255,255,.03) 1px,transparent 1px),

        linear-gradient(90deg,
        rgba(255,255,255,.03) 1px,
        transparent 1px);

    background-size:42px 42px;

    animation:gridMove 25s linear infinite;

    z-index:-2;

}

body::after{

    content:"";

    position:fixed;

    inset:0;

    background:

        radial-gradient(circle,
        transparent 0%,
        rgba(15,23,42,.15) 60%,
        var(--bg) 100%);

    z-index:-1;

}

@keyframes gridMove{

    from{

        transform:translate(0,0);

    }

    to{

        transform:translate(42px,42px);

    }

}

/* ===========================
   Layout
=========================== */

.section{

    width:min(1000px,92%);

    margin:auto;

    padding:70px 0;

}

/* ===========================
   Hero
=========================== */

.hero{

    padding:90px 20px 60px;

    text-align:center;

}

.hero h1{

    font-size:clamp(2.5rem,5vw,4rem);

    font-weight:800;

    letter-spacing:-2px;

    margin-bottom:18px;

}

.subtitle{

    color:var(--muted);

    font-size:1.15rem;

    max-width:650px;

    margin:auto;

}

/* ===========================
   Buttons
=========================== */

.start-btn{

    display:inline-flex;

    align-items:center;

    justify-content:center;

    gap:10px;

    margin-top:35px;

    padding:14px 26px;

    border-radius:14px;

    background:

    linear-gradient(
        135deg,
        var(--primary),
        var(--primary-hover)
    );

    color:white;

    text-decoration:none;

    font-weight:600;

    transition:var(--transition);

    box-shadow:
        0 10px 25px rgba(79,70,229,.25);

}

.start-btn:hover{

    transform:translateY(-3px);

    box-shadow:
        0 15px 35px rgba(79,70,229,.4);

}

/* ===========================
   Glass Card
=========================== */

.card{

    background:
        rgba(30,41,59,.75);

    backdrop-filter:blur(22px);

    border:
        1px solid var(--border);

    border-radius:28px;

    padding:40px;

    box-shadow:var(--shadow);

    transition:var(--transition);

}

.card:hover{

    transform:translateY(-5px);

    border-color:
        rgba(99,102,241,.25);

}

/* ===========================
   Headings
=========================== */

h2{

    font-size:2rem;

    text-align:center;

    margin-bottom:20px;

    font-weight:700;

}

p{

    color:var(--muted);

}
/* =====================================
   Visualised™
   Fractions Stylesheet
   Part 2/3
===================================== */

/* ===========================
   Lesson Card
=========================== */

.lesson-card{

    max-width:900px;

    margin:auto;

}

.lesson-card h2{

    text-align:center;

    margin-bottom:30px;

    font-size:2rem;

}

/* ===========================
   Pie Container
=========================== */

.canvas-container{

    display:flex;

    justify-content:center;

    align-items:center;

    margin:40px 0;

}

#pie{

    width:min(340px,100%);

    aspect-ratio:1;

    display:block;

    cursor:pointer;

    transition:
        transform .45s ease,
        filter .45s ease;

    filter:
        drop-shadow(
            0 0 18px
            rgba(79,70,229,.18)
        );

}

#pie:hover{

    transform:scale(1.03);

    filter:
        drop-shadow(
            0 0 35px
            rgba(99,102,241,.35)
        );

}

/* ===========================
   Controls
=========================== */

.controls{

    display:flex;

    flex-direction:column;

    gap:26px;

    margin-top:20px;

}

.control{

    background:
        rgba(255,255,255,.03);

    border:
        1px solid rgba(255,255,255,.06);

    border-radius:18px;

    padding:20px;

    transition:var(--transition);

}

.control:hover{

    background:
        rgba(255,255,255,.05);

    border-color:
        rgba(99,102,241,.25);

    transform:translateY(-2px);

}

.control label{

    display:flex;

    justify-content:space-between;

    align-items:center;

    margin-bottom:14px;

    font-weight:600;

    color:var(--text);

}

.control span{

    color:var(--primary);

    font-size:1.1rem;

    font-weight:700;

}

/* ===========================
   Modern Slider
=========================== */

input[type="range"]{

    width:100%;

    appearance:none;

    background:transparent;

    cursor:pointer;

}

input[type="range"]::-webkit-slider-runnable-track{

    height:8px;

    background:var(--surface);

    border-radius:999px;

}

input[type="range"]::-webkit-slider-thumb{

    appearance:none;

    width:22px;

    height:22px;

    margin-top:-7px;

    border-radius:50%;

    background:var(--primary);

    border:3px solid white;

    box-shadow:
        0 0 18px
        rgba(79,70,229,.45);

    transition:.25s;

}

input[type="range"]::-webkit-slider-thumb:hover{

    transform:scale(1.15);

    background:var(--primary-hover);

}

/* Firefox */

input[type="range"]::-moz-range-track{

    height:8px;

    background:var(--surface);

    border-radius:999px;

}

input[type="range"]::-moz-range-thumb{

    width:22px;

    height:22px;

    border:none;

    border-radius:50%;

    background:var(--primary);

}

/* ===========================
   Fraction Display
=========================== */

#fractionText{

    display:flex;

    justify-content:center;

    align-items:center;

    min-height:90px;

    margin-top:45px;

    font-size:3rem;

    font-weight:700;

    color:white;

}

#description{

    max-width:620px;

    margin:18px auto 0;

    text-align:center;

    color:var(--muted);

    font-size:1.08rem;

    line-height:1.8;

}

/* ===========================
   Fade Animation
=========================== */

@keyframes fadeUp{

    from{

        opacity:0;

        transform:
            translateY(12px);

    }

    to{

        opacity:1;

        transform:
            translateY(0);

    }

}

.card{

    animation:
        fadeUp .6s ease;

}
/* =====================================
   Visualised™
   Fractions Stylesheet
   Part 3/3
===================================== */

/* ===========================
   Ambient Glow
=========================== */

.lesson-card{
    position:relative;
    overflow:hidden;
}

.lesson-card::before{
    content:"";

    position:absolute;

    width:320px;
    height:320px;

    top:-140px;
    right:-140px;

    border-radius:50%;

    background:
        radial-gradient(
            circle,
            rgba(99,102,241,.18),
            transparent 70%
        );

    pointer-events:none;
}

.lesson-card::after{
    content:"";

    position:absolute;

    width:260px;
    height:260px;

    bottom:-120px;
    left:-120px;

    border-radius:50%;

    background:
        radial-gradient(
            circle,
            rgba(79,70,229,.12),
            transparent 70%
        );

    pointer-events:none;
}

/* ===========================
   Selection
=========================== */

::selection{
    background:var(--primary);
    color:white;
}

/* ===========================
   Links
=========================== */

a{
    color:inherit;
    text-decoration:none;
}

/* ===========================
   Smooth Focus
=========================== */

input:focus{
    outline:none;
}

/* ===========================
   Card Animation
=========================== */

@keyframes floatCard{

    0%{
        transform:translateY(0px);
    }

    50%{
        transform:translateY(-4px);
    }

    100%{
        transform:translateY(0px);
    }

}

.lesson-card:hover{
    animation:floatCard 4s ease-in-out infinite;
}

/* ===========================
   Canvas Transition
=========================== */

#pie{
    transition:
        transform .35s ease,
        filter .35s ease;
}

#pie:active{
    transform:scale(.98);
}

/* ===========================
   Description Fade
=========================== */

#fractionText,
#description{
    transition:
        opacity .25s ease,
        transform .25s ease;
}

/* ===========================
   Utility Classes
=========================== */

.center{
    display:flex;
    justify-content:center;
    align-items:center;
}

.hidden{
    display:none;
}

/* ===========================
   Responsive
=========================== */

@media (max-width:900px){

    .section{
        width:94%;
    }

    .card{
        padding:32px;
    }

}

@media (max-width:700px){

    .hero{
        padding:70px 18px 40px;
    }

    .hero h1{
        font-size:2.6rem;
    }

    #pie{
        width:280px;
    }

    #fractionText{
        font-size:2.4rem;
    }

}

@media (max-width:500px){

    .card{
        padding:24px;
        border-radius:20px;
    }

    .hero h1{
        font-size:2.1rem;
    }

    .subtitle{
        font-size:1rem;
    }

    #pie{
        width:220px;
    }

    #fractionText{
        font-size:2rem;
    }

    #description{
        font-size:.95rem;
    }

    .control{
        padding:16px;
    }

    .start-btn{
        width:100%;
    }

}

const primary = getComputedStyle(document.documentElement)
    .getPropertyValue("--primary")
    .trim();

ctx.fillStyle = i < s ? primary : "#263548";

/* ===========================
   End of Stylesheet
=========================== */