/* ==============================
   项目20：告示板
   Notice Board
   ============================== */

/* ========== 全局样式 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    background: #2c1810;
    min-height: 100vh;
    padding: 40px 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

/* ========== 标题栏 ========== */
.board-header {
    text-align: center;
    margin-bottom: 50px;
    padding: 30px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 10px;
    border: 3px solid #3d2817;
}

.board-title {
    font-size: 2.5rem;
    color: #f4e4bc;
    margin-bottom: 10px;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.board-subtitle {
    font-size: 1.2rem;
    color: rgba(244, 228, 188, 0.7);
    font-weight: 400;
    letter-spacing: 2px;
}

/* ========== 告示板主体（木板背景） ========== */
.notice-board {
    /* 木板背景 - CSS渐变 */
    background:
        /* 横向木纹 */
        repeating-linear-gradient(
            90deg,
            #5d4037 0px,
            #6d4c41 2px,
            #5d4037 4px,
            #4e342e 8px
        ),
        /* 纵向木纹 */
        repeating-linear-gradient(
            0deg,
            rgba(0, 0, 0, 0.1) 0px,
            transparent 2px,
            rgba(0, 0, 0, 0.05) 4px
        ),
        /* 底色 */
        #4e342e;

    background-blend-mode: normal, normal, normal;

    /* 做旧效果 */
    position: relative;
    padding: 60px 40px;
    border-radius: 15px;
    border: 8px solid #3e2723;
    box-shadow:
        inset 0 0 50px rgba(0, 0, 0, 0.5),
        0 10px 40px rgba(0, 0, 0, 0.6);
}

/* 木板划痕效果 */
.notice-board::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        /* 随机划痕 */
        linear-gradient(45deg, transparent 40%, rgba(0, 0, 0, 0.1) 45%, transparent 50%),
        linear-gradient(-45deg, transparent 40%, rgba(0, 0, 0, 0.1) 45%, transparent 50%);
    background-size: 100px 100px, 80px 80px;
    pointer-events: none;
    border-radius: 15px;
}

/* ========== 网格布局 ========== */
.notice-board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px 30px;
}

/* ========== 信纸卡片 ========== */
.paper-card {
    position: relative;
    background: #f5e6c8;
    padding: 30px 25px 25px;
    border-radius: 3px;
    box-shadow:
        0 2px 8px rgba(0, 0, 0, 0.3),
        inset 0 -1px 3px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    min-height: 200px;
    display: flex;
    flex-direction: column;
}

/* 泛黄旧纸纹理 */
.paper-card {
    background:
        /* 纸张纹理 */
        repeating-linear-gradient(
            0deg,
            transparent,
            transparent 2px,
            rgba(139, 119, 85, 0.03) 2px,
            rgba(139, 119, 85, 0.03) 4px
        ),
        /* 泛黄底色 */
        linear-gradient(
            to bottom right,
            #f9f1dc 0%,
            #f5e6c8 50%,
            #e8d5b0 100%
        );
}

/* 悬停效果 */
.paper-card:hover {
    transform: translateY(-5px);
    box-shadow:
        0 8px 20px rgba(0, 0, 0, 0.4),
        inset 0 -1px 3px rgba(0, 0, 0, 0.1);
}

/* ========== 图钉（左上角） ========== */
.pin {
    position: absolute;
    top: -10px;
    left: 20px;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, #9e9e9e, #616161, #424242);
    box-shadow:
        0 2px 4px rgba(0, 0, 0, 0.4),
        inset 0 1px 2px rgba(255, 255, 255, 0.3);
    z-index: 10;
}

/* 图钉头部 */
.pin::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 8px;
    height: 8px;
    background: radial-gradient(circle at 40% 40%, #bdbdbd, #757575);
    border-radius: 50%;
}

/* 图钉针（穿过纸张的效果） */
.pin::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 2px;
    height: 2px;
    background: #424242;
    border-radius: 50%;
}

/* ========== 信纸内容 ========== */
.paper-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

/* 分类标签 */
.category-tag {
    display: inline-block;
    background: rgba(139, 119, 85, 0.2);
    color: #5d4e37;
    padding: 4px 12px;
    border-radius: 3px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 15px;
    border: 1px solid rgba(139, 119, 85, 0.3);
    align-self: flex-start;
}

/* 标题 */
.paper-title {
    font-family: 'Satisfy', cursive;  /* 手写字体 */
    font-size: 1.8rem;
    color: #3e2723;
    margin-bottom: 20px;
    font-weight: 400;  /* Satisfy 字体不需要粗体 */
    line-height: 1.4;
    flex: 1;
}

/* 链接按钮 */
.paper-link {
    display: inline-block;
    color: #5d4e37;
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    padding: 8px 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s ease;
    align-self: flex-start;
}

.paper-link:hover {
    color: #3e2723;
    border-bottom-color: #5d4e37;
}

/* ========== 响应式设计 ========== */
@media (max-width: 1024px) {
    .notice-board {
        grid-template-columns: repeat(2, 1fr);
        gap: 30px 20px;
        padding: 40px 30px;
    }

    .paper-title {
        font-size: 1.3rem;
    }
}

@media (max-width: 768px) {
    .notice-board {
        grid-template-columns: 1fr;
        gap: 25px;
        padding: 30px 20px;
    }

    .board-header {
        padding: 20px;
        margin-bottom: 30px;
    }

    .board-title {
        font-size: 2rem;
    }

    .board-subtitle {
        font-size: 1rem;
    }

    .paper-card {
        min-height: 180px;
        padding: 25px 20px 20px;
    }

    .pin {
        left: 15px;
    }
}