/* =====================================================
   TEACHFLOW AI - SUPERHERO THEME
   ===================================================== */

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

body {
    font-family: Arial, Helvetica, sans-serif;

    min-height: 100vh;

    background:
        radial-gradient(
            circle at 80% 20%,
            rgba(255, 30, 60, 0.25),
            transparent 30%
        ),
        radial-gradient(
            circle at 20% 80%,
            rgba(80, 40, 255, 0.18),
            transparent 30%
        ),
        #070914;

    color: white;

    overflow-x: hidden;
}


/* =====================================================
   BACKGROUND WEB EFFECT
   ===================================================== */

body::before {

    content: "";

    position: fixed;

    inset: 0;

    pointer-events: none;

    opacity: 0.15;

    background-image:
        linear-gradient(
            30deg,
            transparent 48%,
            rgba(255,255,255,0.35) 49%,
            transparent 50%
        ),
        linear-gradient(
            150deg,
            transparent 48%,
            rgba(255,255,255,0.35) 49%,
            transparent 50%
        );

    background-size: 100px 100px;

    mask-image:
        radial-gradient(
            circle at center,
            black,
            transparent 70%
        );
}


/* =====================================================
   APP
   ===================================================== */

.app {

    display: flex;

    min-height: 100vh;

}


/* =====================================================
   SIDEBAR
   ===================================================== */

.sidebar {

    width: 260px;

    min-height: 100vh;

    padding: 25px 18px;

    background:
        linear-gradient(
            180deg,
            rgba(15,17,35,0.98),
            rgba(7,9,20,0.98)
        );

    border-right:
        1px solid
        rgba(255,255,255,0.08);

    position: relative;

    z-index: 2;

}


/* =====================================================
   LOGO
   ===================================================== */

.logo {

    display: flex;

    align-items: center;

    gap: 12px;

    margin-bottom: 30px;

}


.logo-icon {

    width: 45px;

    height: 45px;

    display: flex;

    align-items: center;

    justify-content: center;

    border-radius: 14px;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #8b001b
        );

    font-size: 22px;

    font-weight: bold;

    box-shadow:
        0 0 25px
        rgba(255,23,68,0.5);

}


.logo h2 {

    font-size: 21px;

}


.logo span {

    color: #9da3b4;

    font-size: 12px;

}


/* =====================================================
   NEW LESSON BUTTON
   ===================================================== */

.new-chat {

    width: 100%;

    padding: 13px;

    border: none;

    border-radius: 12px;

    color: white;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #d50032
        );

    font-size: 14px;

    cursor: pointer;

    box-shadow:
        0 0 20px
        rgba(255,23,68,0.25);

    transition: 0.25s;

}


.new-chat:hover {

    transform: translateY(-2px);

    box-shadow:
        0 0 30px
        rgba(255,23,68,0.5);

}


/* =====================================================
   SIDEBAR TITLE
   ===================================================== */

.sidebar-title {

    margin-top: 35px;

    margin-bottom: 15px;

    color: #70778c;

    font-size: 11px;

    text-transform: uppercase;

    letter-spacing: 1.5px;

}


/* =====================================================
   HISTORY
   ===================================================== */

.history {

    display: flex;

    flex-direction: column;

    gap: 8px;

}


.history-item {

    padding: 12px;

    border-radius: 10px;

    color: #bfc4d4;

    cursor: pointer;

    transition: 0.2s;

}


.history-item:hover {

    background:
        rgba(255,255,255,0.06);

    color: white;

}


/* =====================================================
   SIDEBAR BOTTOM
   ===================================================== */

.sidebar-bottom {

    position: absolute;

    bottom: 25px;

    left: 18px;

    right: 18px;

}


.sidebar-option {

    padding: 12px;

    color: #9da3b4;

    cursor: pointer;

    border-radius: 10px;

}


.sidebar-option:hover {

    background:
        rgba(255,255,255,0.06);

    color: white;

}


/* =====================================================
   MAIN
   ===================================================== */

.main {

    flex: 1;

    min-width: 0;

    display: flex;

    flex-direction: column;

    position: relative;

}


/* =====================================================
   HEADER
   ===================================================== */

.header {

    height: 75px;

    padding: 0 30px;

    display: flex;

    align-items: center;

    justify-content: space-between;

    border-bottom:
        1px solid
        rgba(255,255,255,0.07);

    background:
        rgba(7,9,20,0.65);

    backdrop-filter:
        blur(15px);

}


.header h3 {

    font-size: 17px;

}


.online {

    display: block;

    margin-top: 4px;

    color: #43e97b;

    font-size: 11px;

}


.profile {

    width: 40px;

    height: 40px;

    border: none;

    border-radius: 50%;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #673ab7
        );

    color: white;

    font-weight: bold;

}


/* =====================================================
   CHAT AREA
   ===================================================== */

.chat-area {

    flex: 1;

    padding: 40px;

    overflow-y: auto;

}


/* =====================================================
   WELCOME
   ===================================================== */

.welcome {

    max-width: 850px;

    margin: 50px auto;

    text-align: center;

}


.welcome-icon {

    width: 70px;

    height: 70px;

    margin: auto;

    display: flex;

    align-items: center;

    justify-content: center;

    border-radius: 22px;

    font-size: 32px;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #673ab7
        );

    box-shadow:
        0 0 45px
        rgba(255,23,68,0.35);

}


.welcome h1 {

    margin-top: 25px;

    font-size: 42px;

    background:
        linear-gradient(
            90deg,
            white,
            #ff4d6d,
            #b388ff
        );

    -webkit-background-clip: text;

    color: transparent;

}


.welcome p {

    margin-top: 12px;

    color: #9da3b4;

}


/* =====================================================
   SUGGESTIONS
   ===================================================== */

.suggestions {

    margin-top: 35px;

    display: grid;

    grid-template-columns:
        repeat(2, 1fr);

    gap: 15px;

}


.suggestions button {

    display: flex;

    align-items: center;

    gap: 15px;

    text-align: left;

    padding: 18px;

    border-radius: 16px;

    border:
        1px solid
        rgba(255,255,255,0.08);

    background:
        rgba(255,255,255,0.04);

    color: white;

    cursor: pointer;

    transition: 0.3s;

    backdrop-filter:
        blur(15px);

}


.suggestions button:hover {

    transform:
        translateY(-4px);

    border-color:
        rgba(255,23,68,0.6);

    background:
        rgba(255,23,68,0.08);

    box-shadow:
        0 10px 35px
        rgba(0,0,0,0.3);

}


.suggestions button > span {

    font-size: 28px;

}


.suggestions b {

    display: block;

    margin-bottom: 5px;

}


.suggestions small {

    color: #8f96a8;

}


/* =====================================================
   INPUT
   ===================================================== */

.input-container {

    padding: 20px 40px;

}


.input-box {

    max-width: 900px;

    margin: auto;

    display: flex;

    align-items: center;

    gap: 10px;

    padding: 10px 12px;

    border:
        1px solid
        rgba(255,255,255,0.1);

    border-radius: 18px;

    background:
        rgba(255,255,255,0.05);

    backdrop-filter:
        blur(20px);

    box-shadow:
        0 15px 40px
        rgba(0,0,0,0.3);

}


.input-box textarea {

    flex: 1;

    resize: none;

    border: none;

    outline: none;

    background: transparent;

    color: white;

    font-size: 15px;

    padding: 10px;

}


.input-box textarea::placeholder {

    color: #70778c;

}


.icon-button {

    border: none;

    background: transparent;

    color: #9da3b4;

    font-size: 19px;

    cursor: pointer;

}


.send-button {

    width: 42px;

    height: 42px;

    border: none;

    border-radius: 12px;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #d50032
        );

    color: white;

    cursor: pointer;

    font-size: 18px;

}


.disclaimer {

    text-align: center;

    margin-top: 10px;

    color: #555b6d;

    font-size: 10px;

}


/* =====================================================
   LESSON LOADING
   ===================================================== */

.lesson-loading {

    text-align: center;

    margin-top: 120px;

}


.loading-icon {

    font-size: 55px;

    animation:
        pulse 1.3s infinite;

}


@keyframes pulse {

    0% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.15);
    }

    100% {
        transform: scale(1);
    }

}


/* =====================================================
   LESSON PAGE
   ===================================================== */

.teaching-page {

    max-width: 1000px;

    margin: auto;

}


.lesson-header {

    display: flex;

    align-items: center;

    gap: 20px;

    margin-bottom: 25px;

}


.back-button {

    border: none;

    background:
        rgba(255,255,255,0.06);

    color: white;

    padding: 10px 15px;

    border-radius: 10px;

    cursor: pointer;

}


.lesson-header h2 {

    font-size: 24px;

}


.lesson-header span {

    color: #8f96a8;

    font-size: 12px;

}


/* =====================================================
   WHITEBOARD
   ===================================================== */

.whiteboard {

    min-height: 430px;

    padding: 45px;

    border-radius: 25px;

    background:
        #fff;

    color: #171923;

    box-shadow:
        0 25px 70px
        rgba(0,0,0,0.45);

    position: relative;

    overflow: hidden;

}


/* red corner */

.whiteboard::before {

    content: "";

    position: absolute;

    width: 180px;

    height: 180px;

    top: -100px;

    right: -100px;

    border-radius: 50%;

    background:
        #ff1744;

    opacity: 0.12;

}


.whiteboard h2 {

    color: #d50032;

    margin-bottom: 30px;

}


.handwriting {

    font-family:
        "Comic Sans MS",
        cursive;

    font-size: 25px;

    line-height: 1.8;

    white-space: pre-wrap;

}


/* =====================================================
   TEACHER BOX
   ===================================================== */

.teacher-box {

    margin-top: 20px;

    padding: 20px;

    display: flex;

    gap: 15px;

    border-radius: 18px;

    background:
        rgba(255,255,255,0.05);

    border:
        1px solid
        rgba(255,255,255,0.08);

}


.teacher-icon {

    width: 45px;

    height: 45px;

    display: flex;

    align-items: center;

    justify-content: center;

    border-radius: 50%;

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #673ab7
        );

}


.teacher-box b {

    font-size: 14px;

}


.teacher-box p {

    margin-top: 6px;

    color: #aeb4c5;

    line-height: 1.6;

}


/* =====================================================
   CONTROLS
   ===================================================== */

.lesson-controls {

    display: flex;

    justify-content: center;

    gap: 12px;

    margin-top: 25px;

}


.lesson-controls button {

    padding: 12px 20px;

    border: none;

    border-radius: 12px;

    background:
        rgba(255,255,255,0.06);

    color: white;

    cursor: pointer;

}


.lesson-controls .play-button {

    background:
        linear-gradient(
            135deg,
            #ff1744,
            #d50032
        );

    padding-left: 28px;

    padding-right: 28px;

}


.lesson-actions {

    display: flex;

    justify-content: center;

    gap: 10px;

    margin-top: 12px;

}


.lesson-actions button {

    padding: 9px 15px;

    border-radius: 10px;

    border:
        1px solid
        rgba(255,255,255,0.08);

    background:
        rgba(255,255,255,0.03);

    color: #aaa;

    cursor: pointer;

}


/* =====================================================
   ERROR
   ===================================================== */

.lesson-error {

    text-align: center;

    margin-top: 100px;

}


.lesson-error h2 {

    color: #ff4d6d;

}


.lesson-error p {

    color: #9da3b4;

    margin: 15px;

}


/* =====================================================
   MOBILE
   ===================================================== */

@media (max-width: 800px) {

    .sidebar {

        display: none;

    }


    .header {

        padding: 0 18px;

    }


    .chat-area {

        padding: 20px;

    }


    .welcome {

        margin: 35px auto;

    }


    .welcome h1 {

        font-size: 30px;

    }


    .suggestions {

        grid-template-columns: 1fr;

    }


    .input-container {

        padding: 15px;

    }


    .whiteboard {

        padding: 25px;

        min-height: 350px;

    }


    .handwriting {

        font-size: 20px;

    }

}